Background: Despite considerable racial and geographical differences in human phenotypes and in the incidence of diseases that may be associated with sex steroid action, there are few data concerning variation in sex steroid levels among populations. We designed an international study to determine the degree to which geography and race influence sex steroid levels in older men. Methods: Using mass spectrometry, concentrations of serum androgens, estrogens, and sex steroid precursors/metabolites were measured in 5003 older men from five countries. SHBG levels were assessed using radioimmunoassay. Results: There was substantial geographical variation in the levels of sex steroids, precursors, and metabolites, as well as SHBG. For instance, Asian men in Hong Kong and Japan, but not in the United States, had levels of total testosterone approximately 20% higher than in other groups. Even greater variation was present in levels of estradiol, SHBG, and dihydrotestosterone. Group differences in body mass index did not explain most geographical differences. In addition, body mass index-independent racial differences were present; Black men had higher levels of estrogens (estradiol, estrone), and Asian men had lower levels of glucuronidated androgen metabolites. Conclusions: On a global scale, there are important geographical and racial differences in the concentrations of serum sex steroids and SHBG in older men.
Bibliographical noteFunding Information:
Funding for this study was provided as follows: United States—National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institute on Aging, National Center for Research Resources, and National Institutes of Health Roadmap for Medical Research under the following grant numbers: U01 AR45580, U01 AR45614, U01 AR45632, U01 AR45647, U01 AR45654, U01 AR45583, U01 AG18197, U01 AG027810, and UL1 RR024140 . Solvay Pharmaceuticals, Inc. provided additional funding. Canada—Endorecherche Inc., Quebec City, provided partial support for steroid assays. Sweden—The Swedish Research Council, the Swedish Foundation for Strategic Research, The ALF/LUA research grant in Gothenburg, Uppsala, and Lund; the Lundberg Foundation; the Torsten and Ragnar Söderberg′s Foundation; and the Novo Nordisk Foundation. Hong Kong—The Hong Kong Jockey Club Osteoporosis Research Fund. Tobago—Funding or in-kind services from the Division of Health and Social Services, Tobago House of Assembly, U.S. Department of Defense contract DAMD 17-99-1-9015 , and grants R01 CA84950 and R25-CA57703 from the National Cancer Institute , and R01-AR049747 from the NIAMS . Japan—Grants-in-Aid for Scientific Research B20390182 ; Collaborating Research with NSF 08033011-00262 from the Ministry of Education, Culture, Sports, Science and Technology ; H17-Men-eki-009, H18-Choujyu-037, and H20-Choujyu-009 from the Ministry of Health, Labor, and Welfare in Japan . Study sponsors had no role in the study or manuscript beyond funding.