Effects of race, cigarette smoking, and use of contraceptive medications on resting energy expenditure in young women

The prevalence of obesity is higher in Black women than in White women (JAM A 1994;272:205-11; Arch Pediatr Adolesc Med 1995; 149:1085-91). Although it has been shown that Black women have a lower resting energy expenditure (R EE), factors affecting REE remain unclear. This 1996-1997 study in Cincinna ti, Ohio, assessed racial differences in REE and their determinants in a bi racial cohort of 152 healthy young women aged 18-21 years. Two indirect cal orimetric measurements were obtained during two overnight hospital admissio ns 10-14 days apart. Body composition was measured by using dual-energy x-r ay absorptiometry. Mean REE (adjusted for body composition, smoking, and co ntraceptive medication use) was significantly (p = 0.04) lower by 71 kcal/d ay in Black women (1,453 (standard error, 21) kcal/day) than in White women (1,524 (standard error, 19) kcal/day). Smoking was associated with a REE t hat was 68 kcal/day higher for both groups (p = 0.03). A trend (p = 0.07) t oward increased REE (by 46 kcal/day) was found with contraceptive medicatio n use. In conclusion, young Black women had a significantly lower REE than did White women. Cigarette smoking significantly increased REE. The apparen t presence of a more parsimonious energy metabolism in Black women suggests that maintenance of energy homeostasis requires particular vigilance in th is high-risk population.