The correlation between obesity and prostate volume in patients with benign prostatic hyperplasia: A prospective cohort study

Abstract

Objective/background:

Benign prostatic hyperplasia (BPH) is increasing substantial burden on health care systems. Men with high body mass index (BMI) have bigger prostate volumes (PV) with subsequent increase in lower urinary tract symptoms (LUTS) than men with normal BMI. The purpose of this research was to investigate the correlation between Obesity and PV in patients with BPH.

Method:

The study included 560 patients (50–80 years) with BPH. Weight and height measured to calculate BMI. TRUS was used to measure PV. Patient demographics such as IPSS score and prostate specific antigen (PSA) were also noted.

Results:

Patients in the study had a mean age of 65.3 ± 9.45 years and the mean BMI was 23.97 ± 4.89 kg/m². The mean PV of each BMI group were 37.45 ± 0.81, 57.89 ± 1.52 and 77.94 ± 2.17 (ml) for normal, overweight and obese groups, respectively, and the average PV score was 57.76 ± 1.50 ml. The mean PSA score was 3.26 ± 0.94 (ng/dl) with a range of 0.6–10.4. There was significant correlation between BMI and PV (p = 0.001) as well as between BMI with PSA and IPSS (p = 0.02, 0.001, respectively).

Conclusion:

The results showing strong correlation between BMI and PV also BMI with PSA and IPSS. Therefore reducing weight may lead to a lower prostate volume in the elderly stage, making LUTS less noticeable and improving quality of life.

Keywords

BPH obesity PSA LUTS TRUS

Introduction

Benign prostatic hyperplasia (BPH) is a common cause of lower urinary tract symptoms (LUTS) in older men.¹ With advancing age prostatic tissue apoptosis failure results in growing prostate gland size.² BPH is more common in men over the age of 40 or in their fifth decade.^3,4 A presumption basis for BPH diagnosis is provided by prostate size.⁵ Males who are obese and older than 40 years old are more likely to have BPH and tumours.^6
–8 Frequency, urgency, post-void dribbling, nocturia, overflow incontinence, and dysuria are among the symptoms of LUTS.⁹ BPH symptoms are due to mainly increase transitional prostatic zone around the urethra. According to estimates, the proportion of BPH in patients (men) older than 60 years old was over 75%.^10,11 Obesity raises intra-abdominal pressure, which leads to worsening of LUTS.^12,13 Inflammation and microvascular illness brought by central adiposity are favourable characteristics such oxidative stress and ischaemia lead to BPH.¹⁴ Chronic inflammation is main root source of pro-growth cytokines and other growth-related factors.¹⁵ According to another theory, altered oestrogen to androgen ratio due increase adipose tissue and lower testosterone levels promotes the development of BPH.¹⁶ Various publications showed obesity increases likelihood of developing BPH and aggravating LUTS.^15
–17

In Our institution, Department of Urology manages large number of BPH patients medically and surgically. This study sought to explore the relationship between obesity and prostatic enlargement (BPH) and identify a risk factors that could be modifiable and could aid in the epidemiologic study of obesity and BPH.

Material and methodology

The Institutional Ethics Committee authorised the study protocol (116MC/EC/2021), which was carried out in accordance with the Declaration of Helsinki’s principles. The study was a prospective cohort analytical study. In total, 560 patients between ⩾50 and <80 ages were seen consecutively in urology outpatient department between January 2022 and March 2023 were recruited following informed and written consent.

Patients those underwent a transrectal ultrasound (TRUS) guided prostate biopsy due to elevated prostate-specific antigen (PSA) levels or abnormal digital rectal examination findings were evaluated prospectively and patient with benign pathology were also included. A clinical evaluation, including the International Prostate Symptom Score (IPSS) questionnaire, PSA level, Body mass index (BMI) and TRUS findings were performed of each BPH patient. The IPSS was used for the evaluation of LUTS. Patients were divided into three groups according to Asian classification of BMI: 18.5–22.9 (normal), 23.0–24.9 (overweight) and >25 (obese). According to the IPSS, LUTS is characterised as mild between 0 and 7, moderate between 8 and 19 and severe between 20 and 35.

Patients using five alfa reductase inhibitor or antiandrogen, bladder stones, neurogenic bladder, previous prostate surgeries, prostate cancer were excluded from the study.

Statistical analysis

The results summarised by percentages and frequencies (categorical variables) and means, percentiles, standard deviations (numerical variables). Associations between variables and outcome were investigated using contingency tables with relative risks and appropriate hypothesis testing. A one-way analysis of variance (ANOVA) was used to assess the relationship between BMI, PV, PSA and IPSS. The relationship between variables was considered positive when the Pearson correlation (r) was greater than zero. A p-value of <0.05 was considered significant.

Results

Subject characteristics

The mean age of the patients was 65.3 ± 9.45 years and mean BMI was 23.97 ± 4.89 kg/m². About 46 (8.3%) were diagnosed with hypertension and 54 (9.7%) with diabetes mellitus.

The BMI distribution of 560 patients were as follows: 161, 182 and 217 in the normal weight (28.75%), overweight (32.5%), and obese (38.75%) groups, respectively (Figure 1). Mean PSA, BMI, PV and IPSS including sub scores according to each age group are shown in Table 1. Tables 2 and 3 shown the comparisons of the study subjects in each group.

Figure 1.

BMI distribution among study participants.

Table 1.

Baseline characteristics of participants.

Characteristics	Descriptive statistics (Mean ± SD)
Age, year	65.3 ± 9.45
Prostate volume (ml)	57.76 ± 1.50
PSA (ng/ml)	3.26 ± 0.94
BMI (kg/m²)	23.97 ± 4.89
IPSS	19.01 ± 5.48

PSA: prostate specific antigen; BMI: body mass index; IPSS: international prostate symptom score.

Table 2.

Mean BMI, PV, PSA, and IPSS according to age group.

Age	BMI	PSA	PV	IPSS
50–59 (n = 140)	23.71 ± 5.18	2.65 ± 0.98	50.96 ± 1.87	17.37 ± 5.89
60–69 (n = 238)	24.76 ± 4.40	3.45 ± 0.87	57.78 ± 1.54	19.72 ± 5.23
70–79 (n = 182)	23.44 ± 5.09	3.68 ± 0.97	64.54 ± 1.09	19.94 ± 5.32

Table 3.

Comparisons of PV, PSA, IPSS in terms of BMI.

Variables	Normal weight (n = 161)	Overweight (n = 182)	Obese (n = 217)	p-Value
Age	64.94 ± 8.43	65.55 ± 8.96	65.41 ± 9.72	0.73
Prostate volume	37.45 ± 0.81	57.89 ± 1.52	77.94 ± 2.17	N to Ov < 0.001
				N to Ob < 0.001
				Ov to Ob < 0.001
PSA	1.33 ± 0.64	3.53 ± 0.84	4.92 ± 1.34	N to Ov < 0.01
				N to Ob < 0.001
				Ov to Ob < 0.05
IPSS	12.56 ± 6.48	21.11 ± 5.64	23.36 ± 4.32	N to Ov < 0.01
				N to Ob < 0.001
				Ov to Ob > 0.05
• Mild (%)	91 (56.52)	14 (7.69)	7 (3.33)
• Moderate (%)	56 (34.78)	105 (57.69)	94 (43.33)
• Severe (%)	14 (8.70)	63 (34.62)	116 (53.34)

Prostate specific antigen

The mean PSA value was 1.33 ± 0.64, 3.53 ± 0.84 and 4.92 ± 1.34 ng/ml in each BMI group. There were significant differences in PSA values among the groups (p < 0.001) (Table 3).

Prostate volume

The mean PV was 37.45 ± 0.81, 57.89 ± 1.52 and 77.94 ± 2.17 ml in each BMI group. PV was largest in the obese group. There were significant differences in PV among the BMI groups (p < 0.001) (Table 3).

International prostate symptom score

The mean IPSS was 12.56 ± 6.48, 21.11 ± 5.64 and 23.36 ± 4.32 in each BMI group. The IPSS and sub scores for LUTS were highest in the obese group. There were significant differences in IPSS among the BMI groups (p < 0.001) (Table 3).

Associations between PSA, PV, IPSS and BMI

We examined the relationships between PSA, PV, IPSSand BMI. In the univariate analysis by Pearson’s correlation coefficient, BMI correlated with PV (p = 0.001), PSA (p = 0.023) and IPSS (p = 0.02). The correlation coefficients of PSA, PV and IPSS were 0.320, 0.142 and 0.470, respectively (Figure 2).

Figure 2.

Univariate analysis by Pearson’s correlation coefficient: (a) correlation between BMI and PSA (p = 0.02), (b) correlation between BMI and PV (p = 0.001) and (c) correlation between BMI and IPSS (p = 0.001).

Discussion

In individuals with benign prostate hyperplasia, we examined the connection between obesity, prostate volume, and IPSS. It was discovered that obese patients had greater prostate volumes and IPSS scores than average people. The prostate volumes and IPSS scores of obese individuals and those in other BMI categories differed statistically significantly. According to research by Lee et al. people with central obesity and obesity in general had larger prostate volumes than those with normal BMIs. The researchers looked at 146 males above 40 age and divided them into two groups based on their waist circumference (WC) and three groups based on their BMI. In comparison to the normal group, the obese group’s prostate size was noticeably larger.¹⁷ Similar to this, research by Matsuda et al.¹⁸ and Kim et al.¹⁹ revealed a positive correlation between BMI and prostate size but these investigations also revealed a negative link between BMI & PSA levels, with high BMI patients having low PSA.

Through an increase in sympathetic nervous system activity, obesity may affect prostatic hypertrophy and aggravate urinary obstructive symptoms.²⁰ In the Prostate Cancer Prevention Trial’s 5600 men who were recruited in the placebo arm and were monitored for 7 years, Kristal et al.²¹ looked at a number of modifiable lifestyle variables connected to the emergence of symptomatic BPH. They discovered a correlation between obesity and rise in symptomatic BPH (IPSS > 14). So, they hypothesised that adult obesity was linked to a greater incidence of LUTS. In the National Health and Nutrition Examination Survey (NHANES) III cohort, Rohrmann et al. looked into the relationship between obesity and LUTS. Obesity decreases serum globulin-binding protein, free and total oestradiol, and free and total testosterone levels and raises oestrogen levels which can proliferate cells of prostate. BPH & LUTS severity are known to be influenced by the oestrogen to androgen ratio and sympathetic activity. Abdominal obesity rises both factors lead to risk for severe LUTS. The relationship between the quality of venous drainage to BPH is another mechanism that explains this risk.²²

There have been a number of recent research on the connections between BMI and BPH characteristics described, however these studies used healthy male populations who went to health promotion centres. In the current study, we examined symptomatic BPH patients who went to the urology department for assessment or therapy. Our study’s objective was to identify the associations between BMI and symptomatic BPH patients. We thus believe that informing BPH patients of the findings of this study may be beneficial. Patients who visited the urology department and were diagnosed having BPH were evaluated. The findings of our study demonstrated that high BMI was associated with higher mean values of PV and IPSS. BMI and PV and IPSS showed a positive link in the correlation study (p = 0.001 and 0.001, respectively).

Study strengths and limitations

The study is from single centre and mostly from urban population of single state, like many other earlier ones, but compare to other studies numbers of patient included were almost highest. Still it needs to include rural and other states population. So, larger multicentre trials are needed.

Conclusion

As quit high amount of participants in our study. So, we can conclude that Obese patients are more likely to develop larger prostate size with more severe LUTS compare to normal BMI patients. Therefore reducing weight may lead to a lower prostate volume making LUTS less noticeable and improving quality of life.

Footnotes

Acknowledgements

We would like to express our special thanks of gratitude to our patients and staff in Urology Department SMS medical college.

Author contributions

Dr Saurabh Kumar Negi, Post-Doctoral Trainee -Conception, Design, Materials, Data collection and processing, Analysis and Interpretation, Writing; Dr. Sandip Desai, Post-Doctoral Trainee - Materials, Data collection and processing, Analysis and Interpretation, Writing, Literature Review; Dr Gaurav Faujdar, Post-Doctoral Trainee - Materials, Data collection and processing, Analysis and Interpretation, Writing, Literature Review; Dr Sanjeev Jaiswal, Asssociate professor- Design, Supervision, Analysis and Interpretation, Writing, Critical Review; Dr. Ram Dayal Sahu, Assistant Professor- Design, Supervision, Analysis and Interpretation, Writing, Critical Review; Dr. Nachiket Vyas, Professor - Design, Supervision, Analysis and Interpretation, Writing, Critical Review; Dr Shivam Priyadarshi,Senior Professor and Head of department- Design, Supervision, Analysis and Interpretation, Writing, Critical Review

Declaration of conflicting interests

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

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Ethics committee approval

Approved by Institutional Ethics Committee.

• Institute name – SMS MEDICAL COLLEGE, JAIPUR, RAJASTHAN, INDIA

• Approval number – 116MC/EC/2021

• Dated – 20/1/2022

Patient consent

Obtained.

ORCID iDs

Saurabh Kumar Negi

Sandip Desai

Gaurav Faujdar

References

Rohrmann

Smit

Giovannucci

, et al Associations of obesity with lower urinary tract symptoms and noncancer prostate surgery in the third national health and nutrition examination survey. Am J Epidemiol 2004; 159: 390–397.

American Urological Association %J Washington DAUA. American Urological Association guideline: management of benign prostatic hyperplasia (BPH) 2010; 21:98–101.

Hassanzadeh

Yavari-kia

Ahmadi-Asrbadr

, et al Non-obstructive lower urinary tract symptoms versus prostate volume in benign prostatic hyperplasia. Pak J Biol Sci 2010; 13(23): 1129–1134.

Jung

Ahn

Song

, et al Obesity as a risk factor for prostatic enlargement: a retrospective cohort study in Korea. Int Neurourol J 2016; 20: 321–328.

Roehrborn

. Benign prostatic hyperplasia: an overview. Rev Urol 2005; 7 Suppl 9(Suppl 9): S3–S14.

Ojewola

Oridota

Balogun

, et al Prevalence of clinical benign prostatic hyperplasia amongst community-dwelling men in a south-western Nigerian rural setting: a cross-sectional study. Afr J Urol 2017; 23(2): 109–115.

Lee

Kozlowski

Grayhack

. Etiology of benign prostatic hyperplasia. Urol Clin North Am 1995; 22(2): 237–246.

Rehman

Hussain

Khan

, et al The association between obesity and prostate volume in patients with benign prostatic hyperplasia. Age 2012; 61: 5–324.

Bhavsar

Verma

. Anatomic imaging of the prostate. Biomed Res Int 2014; 2014:205–210.

10.

Lin

Freedland

. Lifestyle and LUTS: what is the correlation in men? Curr Opin Urol 2015; 25(1): 1.

11.

Wei

Calhoun

Jacobsen

. Urologic diseases in America project: benign prostatic hyperplasia. J Urol 2005; 173(4): 1256–1261.

12.

Flegal

Carroll

Ogden

, et al Prevalence and trends in obesity among US adults, 1999-2000. JAMA 2002; 288: 1723–1727.

13.

Wang

Mao

Lin

, et al Body mass index and risk of BPH: a meta-analysis. Prostate Cancer Prostatic Dis 2012; 15(3): 265–272.

14.

Chughtai

Lee

, et al Role of inflammation in benign prostatic hyperplasia. Rev Urol 2011; 13(3): 147–150.

15.

Penna

Fibbi

Amuchastegui

, et al Human benign prostatic hyperplasia stromal cells as inducers and targets of chronic immuno-mediated inflammation. J Immunol 2009; 182(7): 4056–4064.

16.

Williams

. Aromatase up-regulation, insulin and raised intracellular oestrogens in men, induce adiposity, metabolic syndrome and prostate disease, via aberrant ER-α and GPER signalling. Mol Cell Endocrinol 2012; 351(2): 269–278.

17.

Lee

Min

Choi

, et al Central obesity as a risk factor for prostatic hyperplasia. Obesity 2006; 14(1): 172–179.

18.

Matsuda

Abe

Suda

. [Relation between benign prostatic hyperplasia and obesity and estrogen]. Rinsho Byori 2004; 52(4): 291–294.

19.

Kim

Song

Kim

, et al Effect of obesity on prostate-specific antigen, prostate volume, and international prostate symptom score in patients with benign prostatic hyperplasia. Korean J Urol 2011; 52(6): 401–405.

20.

Dahle

Chokkalingam

Gao

, et al Body size and serum levels of insulin and leptin in relation to the risk of benign prostatic hyperplasia. J Urol 2002; 168(2): 599–604.

21.

Kristal

Arnold

Schenk

, et al Race/ethnicity, obesity, health related behaviors and the risk of symptomatic benign prostatic hyperplasia: results from the prostate cancer prevention trial. J Urol 2007; 177(4): 1395–1400.

22.

Rohrmann

Smit

Giovannucci

, et al Association between markers of the metabolic syndrome and lower urinary tract symptoms in the third national health and nutrition examination survey (NHANES III). Int J Obes 2005; 29(3): 310–316.