Evaluation of school-based iron supplementation adherence and determinant factors among adolescent girls in Indonesian settings

Abstract

Background

School-based iron supplementation is a key national intervention to reduce anaemia among adolescent girls, however evaluation regarding processes is lacking. This study evaluated adherence to iron supplementation and its determinant factors among schoolgirls in Indonesian settings.

Methods

A cross-sectional study was conducted at selected schools in priority areas of East Java (n = 3) and Bali (n = 4) from April-September 2023. A questionnaire administered to approximately 100 girls at each school collected data on the individual factors and adherence. School databases and interviews with 7 health unit staff was used to understand the environmental factors, and content analysis elicited the themes. Binary logistic regression summarised associations of individual and environmental factors contributing to adherence.

Results

A total of 694 girl respondents reported a mean adherence of 40%. Environmental themes included location (East Java/Bali), type and level of schools (private/public and Junior/Senior High School), iron tablet distribution and administration mechanisms (1-week supply/1-month supply/varied and weekly program at school/self-administered at home/no fixed program). Binary logistic regression confirmed that individual associations (i.e., attitude, Odds Ratio (OR) 2.69; peer support, OR 2.03), and environmental factors (i.e., type of school, OR 7.41; location, OR 2.38; administration mechanisms, OR 8.80) were independently associated with adherence.

Conclusion

Low adherence levels among schoolgirls reported in this study warrants attention. Identified contributing factors provide a basis for the development of strategies to improve adherence to school-based iron supplementation programs in Indonesian settings, particularly at priority areas.

Keywords

adolescent girls iron adherence anaemia

Introduction

Anaemia is a global public health concern and indicates reduced red blood cells and therefore lower than normal haemoglobin concentrations.¹ In 2019, anaemia affected 29.9% in women of reproductive age (15–49 years of age), in which menstruating adolescent girls were among the most vulnerable groups.¹ Anaemia in adolescent girls has negative consequences on school performance, productivity, and current and future reproductive health; they have a higher risk of becoming anaemic women of childbearing age. Infants born to anaemic mothers are associated with increased risks of stunting and perinatal mortality.^2,3 Efforts has been made to meet the World Health Assembly’s target of a 50% reduction in anemia in women of reproductive age (aged 15–49 years) by 2025.⁴ A key action recommended by the World Health Organization (WHO) is increasing consumption of certain micronutrients, including but not limited to iron and folic acid.⁵ Intermittent iron and folic acid supplementation (administered at least once weekly for 3 months, twice yearly, or after the school semester) is recommended in settings where anaemia prevalence in women of reproductive age indicates a public health concern (anaemia >20%).⁶

Indonesia is among the top-10 highest prevalence countries for anaemia in South East Asia,¹ and the latest Indonesian Health Survey in 2023 reported that 15.5% of adolescents were anaemic.^7,8 In accordance with the WHO recommendation, the Indonesian Government has introduced iron supplementation (which consists of 60 mg elemental iron and 0.4 mg folic acid) for adolescent girls as a national nutritional intervention since 2014.⁹ Further, arrangements specified in the Ministry of Health circulatory letter recommends once weekly supplementation for the whole school year. The program is targeted at girls 12–18 years of age, and is distributed via the School Health Unit [Unit Kesehatan Sekolah/Madrasah (UKS/M)] at junior/senior high school levels, and provided free of charge. It was suggested to assign ‘1 day of taking iron supplementation together’ each week based on an agreement with local stakeholders.¹⁰

One key indicator established by the Indonesian Government to evaluate the effectiveness of the school-based iron supplementation program was adherence, particularly since haemoglobin tests have not always been possible due to limited local budgets. Previous Indonesian studies have reported that adherence rates vary significantly across areas, such as East Kalimantan (1.4%), Jakarta, West Java (45.6%) and Yogyakarta, Central Java (62.1%).^11–13 Adherence is acknowledged as a multifactorial phenomenon which can be influenced by many factors.¹⁴ A recent systematic review, which included 20 international studies (i.e., India, Indonesia, Iran, Ghana, Ethiopia and Burkina Faso), has classified determinants of adherence to iron supplementation among adolescent girls into four general categories: 1) personal; 2) social; 3) environmental; and 4) regimen/drug factors.¹⁵ However, this review included only one Indonesian study which indicated issues with regimen [i.e., unpleasant taste and smell (p < 0.01), experiencing side effects (nausea) (p = 0.02)], personal factors [i.e., forgetfulness (p = 0.04)], and social factors [i.e., lack of peer support (p = 0.03)].¹⁵ Further exploration is required to understand the issues of adherence among schoolgirls, particularly in variious priority settings with high prevalence levels of anaemia and/or stunted children.

This study aims to evaluate adherence to iron supplementation and its determinant factors among adolescent schoolgirls in priority areas in East Java and Bali Provinces, Indonesia. Findings of this study should provide evidence-based information for stakeholders to design strategies for sub-national and national scale-up programs of iron supplementation, as well as information on the school-base modality of iron supplementation, particularly in priority settings with high prevalence of anaemia and/or stunted children.

Method

A cross-sectional study in priority areas in Indonesia was conducted. The data collection instrument and methodology used in this study were approved by the Ethics Committee of University of Surabaya (Number 154/KE/VI/2023), and this study granted official permission from the local health offices and related schools as the research settings.

Study settings

This study was conducted in East Java and Bali Provinces. East Java Province has the second largest economy in Indonesia which is dominated by industrial operations, and most of the population is Muslim.¹⁶ While Bali Province has been dominated by tourism with >80% of the population Hindu.¹⁷ No complete data-set of anaemia prevalence of adolescents across areas in East Java and Bali was available, hence two areas in East Java (i.e., PA and BU) and one area in Bali (i.e., DP) were selected by the provincial health offices' staff since those areas were considered stunting priority areas, and therefore iron supplementation priority areas. Further, the same staff selected three schools in East Java [i.e., one private and one public JHS (in PA area), and one public JHS (in BU area)], and four schools in Bali [i.e., one private and one public junior high school (JHS), and one public and one private senior high school (SHS) in DP area] as the research settings. The selection was based on the available data on schools provided with iron supplementation supply within the last 6 months and had high anaemic cases (>50%) based on the random haemoglobin tests or physical checks (e.g., pallor) in the first trimester of 2023 – it should be noted that these data were not available for all schools in those areas.

Data collection

Individual factors and adherence

A questionnaire was developed to collect data on individual factors and adherence among schoolgirls based on current literature.^18–24 The questionnaire was face-validated with an expert panel with one pharmacy practice expert, one public health expert, and 1 health policy expert to ensure the questions addressed the study objectives. Most of the questions were closed-ended questions with binary formats as limited time was available to complete the questionnaire during class (approximately 20 min); literature suggested that binary formats were easier to understand and involved less time and costs.²⁵ The final questionnaire consisted of three sections (Sections A-C) as Supplementary Material available only on-line.

(1) Section A: “Participant characteristics”, including age.

(2) Section B: “Individual Factors” included:

• Internal factors, including:

- Knowledge (20 True/False questions): for each question, one point was given for the correct answer, and 0 point was given for the wrong answer. The total score of the correct answers from each participant was calculated, and converted to a percentage [i.e., total score/20 (maximum score) x 100%].^21–23

- Attitude (16 Agree/Disagree statements): the positive statements were scored 0 point for ‘Disagree’, and one point for ‘Agree’, while reversed scores were applied for negative statements. The total score from all questions was calculated for each participant, and converted to a percentage [i.e., total score/16 (maximum score) x 100%].^21–23

- Other (an open-ended question).

• Drug factors, including: side effects (6 Yes/No questions of common side effects, such as nausea, vomiting, abdominal pain); organoleptic issues (3 Yes/No questions for issues with taste, odour, and/or colour; and other (an open-ended question)

• Social factors, i.e., social support experienced by adolescents to improve compliance of iron supplementation, including: family support (13 Yes/No statements), peer support (10 Yes/No statements), and school representative support (5 Yes/No statements). For each statement, one point was given for ‘Yes’, and 0 was given for ‘No’. The sum of points was calculated for all statements, and converted to a percentage [i.e., total score/maximum score x 100%].

(3) Section C: “Adherence” was assessed using a Yes/No question: “Have you regularly taken iron tablets (i.e., one tablet per week) over the last 3 months?”

The questionnaire was piloted with 30 adolescent girls in a school other than the research settings. Cronbach’s alpha values for internal consistency for knowledge (α = 0.836), attitudes (α = 0.842), family support (α = 0.770), school representative support (α = 0.724), and peer support (α = 0.730); all of which were considered acceptable (>0.7).²⁶

The populations of adolescent girls at the research setting schools are reported in Table 1. Samples required for each school were calculated using simple random sampling (SRS) methods assuming a confidence level of 95%, population proportion of 50%, and margin of error of 10%, which resulted in a minimum sample size of 97 (≈100).²⁷ Random sampling used SPSS (software version 24) to select the samples from each school.

Table 1.

Population sampling frames of adolescent girls at the research setting schools.

East Java Province		Bali Province
PA area	BU area	DP area	DP area
1 public JHS (n = 529 girls)	1 public JHS (n = 467 girls)	1 public JHS (n = 819 girls)	1 public SHS (n = 776 girls)
1 private JHS (n = 322 girls)		1 private JHS (n = 248 girls)	1 private SHS (n = 182 girls)

Abbreviations: JHS, junior high school; SHS, senior high school.

The girls were invited at a face-to-face session arranged by the school, and their parents/guardians were informed about the nature of the study via a school announcement by the researchers (NL,CH, LPS). Parental/guardian consents were obtained from all adolescent girls under 18 years of age. Those who provided consent were asked to complete the questionnaire; this process was assisted by two data collectors who read the questions and asked the students to write down their individual responses to the questionnaire sheets. The data collectors attended a briefing session and simulations until they could perform the data collection functions without errors.

Environmental factors

Environmental factors of the schools included location, type/level of schools, and iron tablet distribution and administration mechanisms. School databases were used to confirm information on the location (i.e., East Java/Bali Provinces), and type and level of the school (i.e., private/public and JHS/SHS); while face-to-face interviews with seven school health unit staff (i.e., one staff per school) – as the person in charge of iron supplementation programs – were used to inform the distribution and administration mechanisms. Whilst the government has provided a general guideline for iron tablet supplementation at schools, no specific guideline was available at these schools; hence, distribution and administration of iron tablets was arranged by the health unit staff based on the resources available at each school. The interviews used a semi-structured interview guide to explore two key topics, i.e., the distribution and administration of iron tablets. It should be noted that the seven schools included in this study had received iron supplementation supply within the last 6 months, so issues of environmental factors related to the availability/supply were not relevant.

The interviews were performed by the researchers (NL, CH, LPS) who were Bachelor/Master of Pharmacy students and trained to conduct the interviews. Prior to the interview, the staff were informed about the study, and asked to complete a written informed consent if they agreed to participate. The interviews were conducted in the school health unit over 15–20 min, and were audio-recorded. The data collection occurred from April to September 2023.

Data analysis

Individual factors and adherence

IBM SPSS Statistics version 25.0 (IBM Corp, Armonk, NY, USA) was used for data analysis. Responses from the questionnaires administered to the schoolgirls were summarised using descriptive analysis; the detailed analysis were as follows:

(1) Section A: “Participant characteristics” related to the age was presented as mean ± standard deviation.

(2) Section B: “Individual Factors”

• Internal factors

− Knowledge (20 True/False questions): The total score which was converted into percentage was categorised into “low” (≤55%), “moderate” (>55-≤75%), or “good” (75-100%).^21–23 Then, the absolute and relative (%) frequencies of participants in each category were presented.

− Attitude (16 statements of Agree/Disagree statements): The total score which was converted into percentage was categorised into “negative” (percentage of agreement ≤50%) or “positive” (percentage of agreement >50%).^21–23 The absolute and relative (%) frequencies of participants in each category were presented.

− The open-ended question was analysed using content analysis.^26,27 The responses were coded by the researchers (NL, CH, LPS). If there was a disagreement, a discussion with the research team was carried out to reach a consensus about the code. The frequencies and percentages of the codes were then calculated.

• Drug factors

⁻ The absolute and relative (%) frequencies of participants who provided responses ‘Yes’ or ‘No’ related to side effects and organoleptic issues were presented.

− The open question was analysed using content analysis.²⁸

• Social factors, including:

− A total score of family support (13 Yes/No statements), peer support (5 Yes/No statements) and school support (3 Yes/No statements) were calculated and converted into percentages; this was then categorised into “low support” (≤50% agreement) and “high support” (>50% agreement). The absolute and relative (%) frequencies of participants in each category were presented.

(3) Section C: “Adherence” (a Yes/No question) was analysed using the absolute number and relative (%) frequencies of participants provided responses ‘Yes’ (adherence) or ‘No’ (non-adherence). All calculations were done for each student, and their cohort in each setting as well as for the total.

Environmental factors

School databases were used to confirm themes of the locations and type/level of the schools. Data from the interviews with school health unit staff were analysed using content analysis to inform iron tablet distribution and administration mechanisms. The analysis initially involved verbatim transcription of the interviews and data familiarization; significant statements were then identified and coded.²⁸ The process of coding was conducted manually by cutting and pasting between transcript documents. The initial coding was performed by NL, CH, LPS, and the emerging themes related to iron tablet distribution and administration mechanisms were discussed with the research team to reach a consensus. Finally, examples of responses were selected to illustrate each theme. Data analysis was conducted using the Indonesian language ‘Bahasa’ (as the language used during the interviews); the illustrative verbatim quotes and themes were then translated into English by an academic with competent English language skills. Member-checking was used to enhance trustworthiness.²⁸

Factors contributing to adherence

Univariate analysis with chi-square was used to test the association of each environmental factor or individual factor as the dependent variable with adherence as the independent variable (i.e., a Yes/No binary variable). For the analysis, environmental factors were quantified by calculating numbers of schoolgirls from schools having the same theme (e.g., schools implementing a 1-week supply distribution mechanism). Statistically significant factors were entered into the model binary logistic regression. Odds ratio (OR) together with 95% confidence intervals (CI) more than one and p-value less than 0.05 indicated a statistically significant association.

Results

Environmental factors

Location and type/level of schools

School databases confirmed the three schools located in East Java Province (i.e., two public JHS and one private JHS); and four schools located in Bali Province (i.e., one public JHS and one private JHS; and one public SHS and one private SHS) (Table 2).

Table 2.

Themes on the environmental factors of the schools.

	East Java			Bali
	Public JHS (PA)	Private JHS (PA)	Public JHS (BU)	Private JHS (DP)	Public JHS (DP)	Private SHS (DP)	Public SHS (DP)
Distribution mechanism	1-week supply – the school health unit staff handed the tablets to PMR members to distribute in the classes	1-week supply – the school health unit staff directly distribute the tablets in the classes	1-month supply – the school health unit staff handed the tablets to the class leaders to distribute in the classes	1-month supply – the school health unit staff handed the tablets to PMR members to distribute in the classes	1-week supply – the school health unit staff handed the tablets to PMR members to distribute in the classes	1-month supply – the school health unit staff handed the tablets to PMR members to distribute in the classes	Varied (1 week or 1 month supply) – the school health unit staff handed the tablets to PMR members to distribute in the classes
Administration mechanism	Weekly program of taking together in the class (Thursday)	Weekly program of taking together in the class (Saturday)	Weekly program of taking together in the class (Friday) – the tablets should be brought during the program	Weekly program of taking together in the class (Friday) – the tablets should be brought during the program	No fixed program – sometimes taking together in the class or sometimes self-administered at home	Self-administered at home	No fixed program – sometimes taking together in the class or sometimes self-administered at home

Abbreviations: PMR, Palang Merah Remaja (Adolescent Red Cross); JHS, junior high school; SHS, senior high school; PA, BU, DP – area code.

Distribution mechanisms

Themes emerging for the iron tablet distribution and administration mechanisms were summarised in Table 2; the data achieved saturation. It was reported that all seven schools had their iron tablets supplied from Puskesmas (i.e., a public primary health facility in the district level). The quantity of iron tablets supplied was based on the number of girls in the school; the supply period provided varied between 6 months to 1 year. The iron tablets were delivered to the school health unit staff-member employed as the person in charge of the iron supplementation program.

Whilst the government has provided a general guideline for iron tablet supplementation at schools, no specific guideline was available at these schools. Distribution was arranged by the health unit staff based on the resources available at each school. The staff had either distributed the tablets himself/herself (n = 1 school), or supervised the distribution via a member of Adolescent Red Cross (Palang Merah Remaja, PMR – i.e., a forum for adolescent activities at school which is under the Indonesian Red Cross) (n = 5 schools) or the class leader (i.e., a student appointed as the class representative) (n = 1 school). The tablets were distributed either as 1-week supply (n = 3 schools), or 1-month supply (n = 3 schools) or varied (1-week or 1-month supply, n = 1 school) (Table 2).

Administration mechanisms

Two schools with a 1-week supply followed with a weekly administration process in the class (Table 2). However, ensuring all the girls were present and taking the tablets was identified as a problem; as stated by the staff at the Public JHS (PA area): “Then (the supply was) followed with a program of taking together every Thursday. Though, it is hard to know whether everyone really takes it.” The third school with 1-week supply and the school with varied supply reported no fixed program for iron tablet administration, as reported by the staff at the Public SHS (DP area):“We actually arrange to have a program of taking together every Friday, but sometimes the tablets were taken home, as there is no fixed program yet.”

From 3 schools with 1-month supply, two schools adopted weekly administration. Thus, the tablets should be brought every week during the administration program, which increased the risk of forgetting, as reported by the staff at Private JHS (DP area): “(We have) a program of taking together every Friday… for students who forget to bring their tablets, they would be asked to self-administer at home, thus no assistance provided.” While the third school with 1-month supply asked the students to self-administer the tablet at home due to the time constraints, as stated by the staff at the Private SHS (DP area): “It is not possible to arrange a taking together program due to the busy schedules of the girls, so they were asked to self-administer the tablet at home.

Individual factors

The questionnaire survey involved a random sampling of 100 adolescent girls per school, except for one school (i.e., Private SHS at DP area; n = 94, six did not complete the questionnaire due to urgent needs), thus giving a total sample of 694 (Table 3). The average age groups of participants across JHS and SHS were 13 years and 16 years of age, respectively. Details on individual factors are presented in Table 3.

Table 3.

Individual factors and adherence to iron supplementation among schoolgirls.

	East Java – n (%)				Bali – n (%)
	Public JHS (PA) (n = 100)	Private JHS (PA) (n = 100)	Public JHS (BU) (n = 100)	Total (n = 300)	Private JHS (DP) (n = 100)	Public JHS (DP) (n = 100)	Total (n = 200)	Private SHS (DP) (n = 94)	Public SHS (DP) (n = 100)	Total (n = 194)	Total – n (%)(N = 694)
Characteristics
Age (years, Mean ± SD)	13.7 ± 0.88	13.7 ± 0.68	13.7 ± 0.73	13.7 ± 0.77	13.5 ± 0.90	13.0 ± 0.85	13.2 ± 0.88	16.4 ± 0.77	15.6 ± 0.68	16 ± 0.82	14.2 ± 1.38
Individual factors
Internal factors
Knowledge:
Good	2 (2.0)	2 (2.0)	5 (5.0)	9 (3.0)	10 (10.0)	17 (17.0)	27 (13.5)	12 (12.8)	7 (7.0)	19 (9.8)	55 (7.9)
Moderate	70 (70.0)	58 (58.0)	72 (72.0)	200 (66.7)	62 (62.0)	58 (58.0)	120 (60)	53 (56.4)	65 (65.0)	118 (60.8)	438 (63.1)
Poor	28 (28.0)	40 (40.0)	23 (23.0)	91 (30.3)	28 (28.0)	25 (25.0)	53 (26.5)	29 (30.9)	28 (28.0)	57 (29.4)	201 (29)
Attitude:
Positive	96 (96.0)	100 (100.0)	92 (92.0)	288 (96.0)	86 (86.0)	77 (77.0)	163 (81.5)	76 (80.9)	100 (100.0)	176 (90.7)	627 (90.3)
Negative	4 (4.0)	0 (0.0)	8 (8.0)	12 (4.0)	14 (14.0)	23 (23.0)	37 (18.5)	18 (19.1)	0 (0.0)	18 (9.3)	67 (9.7)
Others:
Forgetfulness	2 (2.0)	4 (4.0)	7 (7.0)	13 (4.3)	5 (5.0)	12 (12.0)	17 (8.5)	20 (21.3)	27 (27.0)	47 (24.2)	77 (11.1)
Drug factors
Side effects:
Yes	48 (48.0)	42 (42.0)	56 (56.0)	146 (48.7)	86 (86.0)	39 (39.0)	125 (62.5)	64 (68.0)	39 (39.0)	103 (53.1)	374 (53.9)
No	52 (52.0)	58 (58.0)	44 (44.0)	154 (51.3)	14 (14.0)	61 (61.0)	75 (37.5)	30 (32.0)	61 (61.0)	91 (46.9)	320 (46.1)
-Nausea (yes)	40 (40.0)	44 (44.0)	49 (49.0)	133 (44.0)	70 (70.0)	23 (23.0)	93 (47.0)	52 (55.0)	30 (30.0)	82 (42.0)	308 (44.0)
-Vomitting (yes)	16 (16.0)	0 (0.0)	13 (13.0)	29 (10.0)	18 (18.0)	15 (15.0)	33 (17.0)	10 (11.0)	6 (6.0)	16 (8.0)	78 (11.0)
-Stomach (yes)	18 (18.0)	6 (6.0)	17 (17.0)	41 (14.0)	38 (38.0)	20 (20.0)	58 (29.0)	12 (13.0)	6 (6.0)	18 (9.0)	117 (17.0)
-Diarrhoea (yes)	6 (6.0)	2 (2.0)	5 (5.0)	13 (4.0)	9 (9.0)	4 (4.0)	13 (6.0)	3 (3.0)	1 (1.0)	4 (2.0)	30 (4.0)
-Constipation (yes)	2 (2.0)	2 (2.0)	5 (5.0)	9 (3.0)	10 (10.0)	0 (0.0)	10 (5.0)	4 (4.0)	1 (1.0)	5 (3.0)	24 (3.0)
-Black/tarry stool (yes)	4 (4.0)	0 (0.0)	9 (9.0)	13 (4.0)	12 (12.0)	2 (2.0)	14 (7.0)	13 (14.0)	5 (5.0)	18 (9.0)	45 (6.0)
Organoleptic problems:
Yes	70 (70)	80 (80)	84 (84)	234 (78)	89 (89.0)	55 (55.0)	144 (72.0)	69 (73.4)	49 (49.0)	118 (60.8)	498 (71.8)
No	30 (30)	20 (20)	16 (16)	66 (22)	11 (11.0)	45 (45.0)	56 (28.0)	25 (26.6)	51 (51.0)	76 (39.2)	196 (28.2)
-Bad taste (yes)	56 (56)	22 (22)	62 (62)	140 (47)	61 (61.0)	36 (36.0)	97 (48.0)	46 (49)	33 (33.0)	79 (41.0)	316 (46.0)
-Bad odour (yes)	66 (66)	48 (48)	70 (70)	184 (61)	64 (64.0)	47 (47.0)	111 (55.0)	55 (59)	41 (41.0)	96 (49.0)	391 (56.0)
-Bad colour (yes)	12 (12.0)	46 (46.0)	22 (22.0)	80 (27.0)	10 (10.0)	1 (1.0)	11 (5.0)	10 (11.0)	1 (1.0)	11 (6.0)	102 (15.0)
Others:
Difficult to swallow	18 (18.0)	14 (14.0)	25 (25.0)	57 (19.0)	17 (17.0)	24 (24.0)	41 (20.0)	36 (38.0)	18 (18.0)	54 (28.0)	152 (22.0)
Social factors
Peer support:
High	48 (48.0)	26 (26.0)	47 (47.0)	121 (40.3)	43 (43.0)	44 (44.0)	87 (43.5)	34 (36.2)	44 (44.0)	78 (40.2)	286 (41.2)
Low	52 (52.0)	74 (74.0)	53 (53.0)	179 (59.7)	57 (57.0)	56 (56.0)	113 (56.5)	60 (63.8)	56 (56.0)	116 (59.8)	408 (58.8)
Family support:
High	16 (16.0)	22 (22.0)	23 (23.0)	61 (20.3)	23 (23.0)	100 (100.0)	123 (61.5)	11 (11.7)	17 (17.0)	28 (14.4)	212 (30.6)
Low	84 (84.0)	78 (78.0)	77 (77.0)	239 (79.7)	77 (77.0)	0 (0.0)	77 (38.5)	83 (88.3)	83 (83.0)	166 (85.6)	482 (69.4)
School representative support:
High	90 (90.0)	88 (88.0)	87 (87.0)	265 (88.3)	76 (76.0)	67 (67.0)	143 (71.5)	57 (60.6)	42 (42.0)	99 (51.0)	507 (73.1)
Low	10 (10.0)	12 (12.0)	13 (13.0)	35 (11.7)	24 (24.0)	33 (33.0)	57 (28.5)	37 (39.4)	58 (58.0)	95 (49.0)	187 (26.9)
Adherence
No	22 (22.0)	68 (68.0)	67 (67.0)	157 (52.0)	51 (51.0)	50 (50.0)	101 (51.0)	94 (100.0)	63 (63.0)	157 (81.0)	415 (60.0)
Yes	78 (78.0)	32 (32.0)	33 (33.0)	143 (48.0)	49 (49.0)	50 (50.0)	99 (49.0)	0 (0.0)	37 (37.0)	37 (19.0)	279 (40.0)

Abbreviations: JHS, junior high school; SHS, senior high school.

Internal factors – less than 10% of adolescent girls had good knowledge regarding iron supplementation, those from public and private JHS (BU area, East Java) had the lowest percentages (2% and 2%, respectively). On the contrary, approximately 90% of the girls across schools had positive attitudes toward the school-based iron supplementation program.

Drug factors – approximately half of the participating girls across schools reported an experience with adverse effects, particularly nausea. Moreover, more than 70% of the girls also indicated issues with organoleptic properties of the iron tablet, particularly in relation with its taste and odour. In addition, approximately 20% of the girls reported other problems, especially difficulty in swallowing the tablet.

Social factors – The majority of girls reported positive support from school representatives, particularly those from JHS (>65%). On the contrary, only approximately 40% of girls across schools have had positive support from their peers; and even less support was indicated from their families (<30%), except those from public JHS in Bali (100%).

Adherence and the determinant factors

The level of adherence among adolescent girls to iron supplementation in the last 3 months varied across schools where girls from SHS in Bali generally had lower adherence (19%). A better adherence of approximately 50% was reported across JHS in Bali as well as East Java.

Univariate analysis was conducted between each of the individual factors as well as the environmental factors versus levels of adherence to iron supplementation (Table 4). Statistically significant associations were reported for some individual factors (including: internal factors – i.e., attitude; drug factors – i.e., side effects; and social factors – i.e., peer family and school representative support) as well as all environmental factors (all p-values <0.05). However, the binary logistic regression confirmed only attitude, peer support, type of school, location and administration mechanism were independently associated with adherence (Table 5). Girls from public schools had an increased odds of 7.41 to have adequate adherence compared to those from private schools (95% CI 3.88-14.15, p < 0.001); while girls from schools with a “taking together” program had an increased odds of 8.80 compared to those from schools without the program (95% CI 3.28-23.63, p < 0.001). Detailed results of the logistic regression can be seen in Table 5.

Table 4.

Univariate analysis between each determinant factor versus adherence (N = 694).

	Adherence			p-value
	No n (%)	Yes n (%)		p-value
Individual factors
Internal factors
Knowledge:
Good/moderate	286 (58.0)	207 (42.0)	0.133
Poor	129 (64.2)	72 (35.8)	0.133
Attitude:
Positive	363 (57.9)	264 (42.1)	0.002
Negative	52 (77.6)	15 (22.4)	0.002
Drug factors
Side effects:
Yes	238 (63.6)	136 (36.4)	0.026
No	177 (55.3)	143 (44.7)	0.026
Organoleptic problems:
Yes	302 (60.6)	196 (39.4)	0.470
No	113 (57.7)	83 (42.3)	0.470
Social factors
Peer support:
Positive	141 (49.3)	145 (50.7)	<0.001
Negative	274 (67.2)	134 (32.8)	<0.001
Family support:
Positive	111 (52.4)	101 (47.6)	0.008
Negative	304 (63.1)	178 (36.9)	0.008
School representative support:
Positive	283 (55.8)	224 (44.2)	<0.001
Negative	132 (70.6)	55 (29.4)	<0.001
Environmental factors
Level of school:
JHS	258 (51.6)	242 (48.4)	<0.001
SHS	157 (80.9)	37 (19.1)	<0.001
Type of school:
Private	213 (72.4)	81 (27.6)	<0.001
Public	202 (50.5)	198 (49.5)	<0.001
School location:
East java	157 (52.3)	143 (47.7)	<0.001
Bali	258 (65.5)	136 (34.5)	<0.001
Distribution mechanisms:
1-week supply	191 (47.8)	209 (52.2)	<0.001
1-month supply	161 (83.0)	33 (27.0)
Varied (1-week/month supply)	63 (63.0)	37 (37.0)
Administration mechanisms:
Weekly program of taking together (at school)	208 (52.0)	192 (48.0)	<0.001
Self-administered at home	113 (56.5)	87 (43.5)
No fixed program	94 (100.0)	0 (0.0)

Abbreviations: JHS, junior high school; SHS, senior high school.

Table 5.

Odds ratios and 95% confidence intervals of significant individual determinant factors associated with adherence.

	Adherence
	Odds ratio	95% CI	p-value
Individual factors
Internal factors
Attitudes:
Positive	2.69	1.33–5.44	0.001
Negative	Reference
Social factors:
Peer support:
Positive	2.03	1.41–2.93	<0.001
Negative	Reference
Environmental factors
Type of school:
Private	Reference
Public	7.41	3.88–14.15	<0.001
School location:
East java	Reference
Bali	2.38	1.28–4.45	0.006
Administration mechanisms:
Weekly program of taking together (at school)	8.80	3.28–23.63	<0.001
Self-administered at home or no fixed program	Reference

Discussion

This study has provided insights regarding important aspects of school-based iron supplementation programs at selected schools in Indonesia, specifically located in the known stunted priority areas in East Java and Bali Provinces. The levels of adherence to iron administration – as one key indicator of the program – varied across schools, but was overall suboptimal with an average of 40%. Suboptimal levels of adherence were also reported in previous Indonesian studies (1.4% - 62.1%);^11–13 while international studies in certain African and Indian regions reported varied levels of adherence (14.5% - 92.3%).¹⁵ Low levels of adherence among schoolgirls warrants attention since adherence to iron supplementation is suggested to be positively associated with serum haemoglobin concentration and negatively associated with anaemia.²⁹ Systematic reviews conducted in 2016 and in 2017 reported that iron supplementation significantly reduced anaemia by 33% and 27% among adolescents (mostly girls), respectively.^30,31 Hence, this study highlighted the importance to optimise processes of school-based iron supplementation to improve adherence, particularly in priority settings.

This present study has indicated that environmental factors (related to the contexts of the schools) have demonstrated significant associations with adherence to iron supplementation, including locations (i.e., East Java), type of schools (i.e., public schools) and administration mechanisms (i.e., weekly program of taking together). The effectiveness of a weekly program of taking together (at the school classroom) was also evidenced in a prior Indonesian study in Jakarta, West Java.¹¹ While this present study indicated that not all schools have implemented a weekly program of taking iron tablets together, broadening the uptake of that program warrants consideration; particular attention should be given to private schools. Unlike public schools, private schools are funded/operated by private sectors and enjoy significant autonomy,³² thus strengthening the implementation of the government’s iron supplementation program, would be essential in these settings.

In general, this study reported lower associations to adherence for individual factors (i.e., social factors, internal, and drug factors) compared to the environmental factors. Social factors related to peer support and was found as a significant predictor. In parallel, prior research in Gujarat, India reported that involving peer educators (under a voluntary organisation) in community-based weekly iron supplementation programs showed promising results in improving adolescent adherence.³³ Peer educator activities also were reported to be able to improve adolescents’ attitudes, normative beliefs, subjective norms, and perceptions of behavioral control in factors relating to prevention of illicit substance abuse.³⁴ However, the influence of social factors seems to be different across settings; a systematic review included studies reported a range of social support can influence adherence to iron supplementation, either from teachers,^35–37 parents,^37,38 family,¹³ or peers.^13,37,38 While this study reported no significant association of family and school representative support to adolescent adherence, further exploration would be required to determine whether support or training are required to enhance their roles in the iron supplementation program.

With regards to the internal factors among adolescent schoolgirls, this present study reported that attitudes have significant associations with adherence; however, no significant association was reported between knowledge and adherence. In contrast, prior international studies have reported knowledge (related anaemia, posistive effects/benefits of iron tablets, iron deficiency issues) can influence adherence.^35,36,39,40 Whilst it is generally acknowleged that better knowledge will lead to improved attitudes and practice;^41,42 in this study, only a small percentage of the girls had good knowledge, but most of them reported positive attitudes. This might be due to the girls’ familiarity with the iron supplementation program (as part of the national program which has been implemented via their schools), however a lack of information or insufficient attention to the relevant knowledge may be factors for further exploration.

This study has some limitations. This study specifically evaluated profiles of adherence among adolescent girls at selected schools in East Java and Bali; thus, some caution should be exercised in generalising these results. However, this study included a range of schools’ characteristics which can provide insights to the broader Indonesian school context. In addition, it should be noted that some self-reported data could be biased when participants could not accurately recall the information asked (recall bias). However, the questionnaire in this study was designed to include information regarding participants’ behaviour in taking iron supplementation over a short period of time, i.e., in the last 3 months, hence issues with recall bias might be minimal. The use of binary formats in this questionnaire forced respondents with an opinion in the middle to transform to an extreme answer, resulting in a higher tendency to agree. However, the use of predictive wording (i.e., refer to what one should do, what is right or wrong, or good or bad) in this questionnaire might help the accuracy of the binary format in providing directions of answers.²⁵

Conclusion

School-based iron supplementation programs in some priority areas in East Java and Bali were sub-optimal, thus requiring additional attention, especially by school health unit staff. Strategies related to environment aspects of the school, in particular implementing a weekly program of taking the iron tablet (directly after being distributed at the school), paying more attention to the private schools, as well as improving peer support, might be considered for a successful implementation of school-based iron supplementation program in priority areas in the low-resource countries. The impacts of the program on the health outcomes beyond adherence, such as in reducing the prevalence of anaemia and child stunting, warrants further long-term exploration.

Supplemental Material

Supplemental material - Evaluation of school-based iron supplementation adherence and determinant factors among adolescent girls in Indonesian settings

Supplemental material for Evaluation of school-based iron supplementation adherence and determinant factors among adolescent girls in Indonesian settings by Adji Prayitno Setiadi, I Gusti Agung Ari Kusuma Yana, Gusti Ayu Putu Laksmi Puspa Sari, Catherina Hutahaean, Ni Nyoman Laila Nordewi Yani, Susilo Ari Wardhani, Bruce Sunderland and Yosi Irawati Wibowo in Community Health Equity Research & Policy

Footnotes

Acknowledgments

We would like to thank the East Java Provincial Health Office, and the participating schools which hosted the survey as well as their staff and students who supported in the data collection.

ORCID iDs

Adji Prayitno Setiadi

I Gusti Agung Ari Kusuma Yana

Gusti Ayu Putu Laksmi Puspa Sari

Bruce Sunderland

Yosi Irawati Wibowo

Ethical considerations

The data collection instrument and methodology used in this study were approved by the Ethics Committee of University of Surabaya, Indonesia (Number 154/KE/VI/2023), and this study granted official permissions from the local health offices and related schools as the research settings. Parents/guardians were informed about the nature of the study via school announcement and were given opportunity to provide written informed consents for their adolescent girls to participate.

Authors’ contributions

APS: methodology, formal analysis, conceptualitation, writing-original draft preparation. YIW: methodology, writing – reviewing and editing. AKY, LPS, CH, LNY: investigation, formal analysis, data curation. SAW: methodology, validation. BS: conceptualisation, writing- reviewing and editing.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author, YIW, upon reasonable request.*

Supplemental Material

Supplemental material for this article is available online.

Author Biographies

Adji Prayitno Setiadi is a Professor in Faculty of Pharmacy, Universitas Surabaya, Indonesia. He is currently the Dean of the faculty, while previously being the director of Centre for Medicines Information and Pharmaceutical Care (CMPIC) from 2015 to 2022. He has awarded several research grants to promote quality use of medications among Indonesians. He has also served as an expert panel in the Ministry of Health Republic of Indonesia in developing policies and guidelines to optimise the role of pharmacists in rational drug therapy. He can be contacted at email: adji_ps@staff.ubaya.ac.id.

I Gusti Agung Ari Kusuma Yana is a lecturer at the Clinical and Community Pharmacy Programme, Institut Teknologi dan Kesehatan Bali, Indonesia. He completed his Master of Pharmacy degree at Universitas Surabaya, Indonesia. His research interest focuses on community pharmacy. He can be contacted at email: agungariigusti@gmail.com.

Gusti Ayu Putu Laksmi Puspa Sari is a lecturer in the Department of Social Pharmacy, Faculty of Pharmacy, Universitas Mahasaraswati Denpasar, Indonesia. She received her Master of Pharmacy degree from Universitas Surabaya, Indonesia. Her research interests lie in pharmacy practice, with a particular focus on self-medication and the role of pharmacists in promoting the safe and rational use of medicines. She can be contacted at email: laksmipuspasari@unmas.ac.id.

Catherina Hutahean is a registered pharmacist who recently completed her professional pharmacy education at Universitas Surabaya in 2024. Currently, he holds the position of assistant pharmacist in a private community pharmacy, dedicating her expertise to optimize pharmacy care and management and ensure that pharmacy services provided to the community are in accordance with applicable standards.

Ni Nyoman Laila Nor Dewi Yani is a licensed pharmacist graduated from the University of Surabaya. She currently serves as the Pharmacist-in-Charge at one of the largest retail pharmacy chains in Indonesia, where her notable achievements include successfully leading several projects and serving as a Supervising Pharmacist for three months.

Susilo Ari Wardhani is the Head of Health Resources Section at East Java Provincial Health Office, Ministry of Health, Republic of Indonesia. She is an active teacher practitioner at Faculty of Pharmacy, Universitas Surabaya, as well as a certified facilitator for pharmacy pre-registration program. She has research collaborations with a range of educational institutions to continuously evaluate the implementation of government interventions and policies in optimising rational use of medications, particularly in East Java region.

Bruce Sunderland is an Emeritus Professor in the School of Pharmacy and Biomedical Sciences, Curtin University. He is active in the areas of pharmacy practice especially community pharmacy practice, drug and antibiotic usage and stability. He has supervised many PhD and research Master of Philosophy theses and published more than 280 research articles in refereed journals. He can be contacted at email: B.Sunderland@curtin.edu.au.

Yosi Irawati Wibowo is a drug information pharmacist at Medicines information and Pharmaceutical Care (CMPIC), and an associate professor in the Faculty of Pharmacy, Universitas Surabaya, Indonesia. She has been involved in numerous research projects in collaboration with the East Java Provincial Health Office to promote rational use of medicines. She has authored or co-authored multiple peer-reviewed scientific papers related to pharmacy practice, and has particular interests in optimising the role of pharmacists and quality use of medications. She can be contacted at email: yosi_wibowo@staff.ubaya.ac.id.

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