A study allegedly linking daily sugar-sweetened beverage (SSB) consumption to earlier menarche has raised concerns about the long-term implications for breast cancer risk. J.L. Carwile, et al., “Sugar-sweetened beverage consumption and age at menarche in a prospective study of US girls,” Human Reproduction, January 2015. Relying on dietary questionnaires completed by 5,583 girls ages 9 to 14 before their first menses, researchers with the Harvard School of Public Health and Brigham and Women’s Hospital reported “more frequent SSB consumption predicted a higher rate of reaching menarche” during five years of follow-up.

After controlling for birth weight, maternal age at menarche, physical activity, and other factors, the study claims that girls who consumed more than 1.5 servings of sugar-sweetened soda, non-carbonated fruit drinks or iced tea per day (i) were 26 percent “more likely to reach menarche in the next month relative to girls who reported consuming [less than] 2 servings of SSBs weekly,” and (ii) attained menarche 2.7 months earlier, even after adjusting for total energy intake. The study’s authors also considered the effect of BMI on age at menarche but apparently found that “BMI explained only 9.2% of the total observed association between SSBs and menarche or BMI and menarche.”

“A 1-year decrease in age at menarche is estimated to increase the risk of breast cancer by 5%,” concludes the study. “Most importantly, the public health significance of SSB consumption on age at menarche, and possibly breast cancer, should not be overlooked, since, unlike most other predictors of menarche, SSB consumption can be modified.”