Greater Short-Term Weight Loss in Women 20–45 versus 55–65 Years of Age Following Bariatric Surgery

Abstract

Background Whether and how sex and age affect bariatric-surgery outcome is poorly understood. Estrogens regulate body composition in women and animals, and increase weight loss in a rodent model of gastric bypass, suggesting that premenopausal women may lose more weight following bariatric surgery. Methods One thousand three hundred fifty-six female gastric-bypass or gastric-banding patients were retrospectively grouped as 20–45 years old (presumptively premenopausal; n = 1,199) and 55–65 years old (presumptively postmenopausal; n = 157). Mixed-model ANCOVA followed by Bonferroni-corrected t tests were used to categorically test the effect of age on percent excess body weight loss (%EBWL) at 1 and 2 years post-surgery, controlling for preoperative EBW and surgery type. Age effects were also tested dimensionally in all women and in 289 male patients. Results Twenty- to forty-five-year-old women showed greater %EBWL 1 and 2 years post-surgery than 55–65-year-old women (p’s < 0.0005). No age effect was detected in 20–25- vs. 30–35-, 30–35- vs. 40–45-, or 20–25- vs. 40–45-year-old women (p’s > 0.2) This age effect was detected only after gastric banding, with 20–45-year-old women losing ∼7 kg more than 55–65-year-old women after 2 years. Dimensional analysis confirmed a significant inverse effect of age on bariatric surgery outcome in women, but did not detect any effect in men. Conclusions Results indicate that 55–65-year-old women lose less weight than 20–45-year-old women in the initial 2 years after bariatric surgery, especially gastric banding; this may be mediated by age- or menopause-associated changes in physical activity, energy expenditure, or energy intake.