Reproductive Hormone Levels Are Not Related to Obesity in Middle-Aged and Elderly South Asian Men: Results of a Multi-Ethnic Cohort Study

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SUN 176-202-Male Reproductive Endocrinology and Male Reproductive Tract (posters)
Bench to Bedside
Sunday, April 3, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SUN 187
Robert J.A.H. Eendebak*1, Martin K. Rutter1, Joseph D. Finn1, Agnieszka Swiecicka1, Piotr S. Gromski2, Alan Marshall3, Brian G. Keevil4, Kennedy Cruickshank5, Gindo Tampubolon1, Royston Goodacre1 and Frederick C. W. Wu1
1University of Manchester, Manchester, United Kingdom, 2University of Glasgow, Glasgow, United Kingdom, 3University of St Andrew's, St Andrew's, United Kingdom, 4University Hospital of South Manchester, Manchester, United Kingdom, 5King's College London, London, United Kingdom
Introduction: Ethnic differences in body composition and obesity, as well as in reproductive hormones (RH) have been documented (1-3). Obesity is strongly associated with variations in levels of RH. However, potential ethnic differences in the relationship between obesity and RH have not been extensively investigated.

Aim and setting: The aim of the study was to investigate the relationship of RH with obesity, as assessed by body mass index (BMI) or waist circumference (WC), in a multi-ethnic cross-sectional cohort study from Manchester (UK) consisting of men of South Asian (SA), African Caribbean (AFC) or White European (WEU) origin participating in the HUSERMET project (4)

Methods: SA (n=180), AFC (n=166) and WEU (n=328) men aged 40-84 years from the general population had single morning blood samples measured for testosterone (T) (by LC MS/MS), SHBG, LH and FSH together with assessment of body composition, carbohydrate metabolism, hematological and cognitive parameters, and self-reported physical activity, sexual, physical, psychological symptoms and medical conditions. Relationships between RH (dependent variables) and BMI or WC (independent variables) were assessed using linear regression. Risk factors for low T levels, such as age, alcohol intake and physical activity were included as covariates. Five-fold cross-validation assessed whether the regressed relationships were robust.

Results: 642 men were included in the analysis (mean±sd age: 59±12 years, age-adjusted mean±se total T and calculated free T of SA, AFC and WEU men were: 14.0±0.4, 17.2±0.5, 17.1±0.3 nmol/L and 282.6±7.1, 314.1±7.6 and 313.3±5.4 pmol/L). For both AFC men and WEU men, BMI was a predictor of total T levels (AFC men: β:-0.36, 95%CI:-0.50;-0.22, and WEU men: β:-0.41, 95%CI:-0.52;-0.30,), calculated free T levels (AFC men: β:-0.24, 95%CI:-0.38;-0.11 and WEU men: β:-0.31, 95%CI:-0.42;-0.20), SHBG levels (AFC men: β:-0.27, 95%CI:-0.43,-0.10 and WEU men: β:-0.30, 95%CI:-0.40,-0.19, but not LH levels (AFC men: β:-0.14, 95%CI:-0.32;0.04, and WEU men: β:-0.07, 95%CI:-0.20;0.06) after full adjustment. However, in SA men, BMI was not related to RH, such as total T (β:-0.07, 95%CI:-0.24;0.09), calculated free T (β:-0.01, 95%CI:-0.17;0.16), SHBG (β:-0.10, 95%CI:-0.26;0.07) and LH levels (β:-0.05, 95%CI:-0.20;0.11) after full adjustment. Similar results were obtained, when using WC as a predictor. Five-fold cross validation displayed similar mean-squared error values across the 3 ethnic groups.

Conclusion: BMI and WC were significantly related to RH in AFC men and WEU men, but not in SA men. Therefore, an individual’s ethnic background should be taken into account when interpreting T results, especially in the context of obesity. Ethnic group – specific reference ranges for T may also need to be considered.

(1) Misra, A. & Vikram, N.K., 2004, Nutrition (Burbank, Los Angeles County, Calif.), 20(5), pp. 482-91. (2) Misra, A. & Khurana, L., 2011, International journal of obesity, 35(2), pp. 167-87. (3) Tchernof, A. & Després, J.P., 2013, Physiological reviews, 93(1), pp. 359-404. (4) Dunn, W.B., et al., 2015, Metabolomics, 11(1), pp. 9-26.

Disclosure: FCWW: Consultant, Repros Therapeutics, Investigator, Besins Healthcare, Speaker, Besins Healthcare. Nothing to Disclose: RJAHE, MKR, JDF, AS, PSG, AM, BGK, KC, GT, RG

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting/pr-resources-for-endo

Sources of Research Support: RJAHE is supported by a Biotechnology and Biological Sciences Research Council – Doctoral Training Partnership PhD-fellowship and is grateful for receiving support from the Fundatie van de Vrijvrouwe van Renswoude and Scholten-Cordes scholarship foundations