Early natural menopause experienced by women in the prospective Nurses’ Health Study 2 was associated with a younger age at menarche and shorter and more regular cycles, according to a study published in The Journal of Clinical Endocrinology & Metabolism.
Using the prospective Nurses’ Health Study 2 (1989 to 2011), the current study used Cox proportional hazards models to analyze data for women who were both premenopausal and between the ages of 25 and 42 in 1989 (N=108,811).
Analysis discovered that a higher risk for early natural menopause (defined as occurring before age 45) was associated with shorter and more regular cycles (P <.0001 and P <.0001, respectively) and younger age at menarche (P =.05).
Women who reported menstrual cycles shorter than 25 days from age 18 to 22 had a higher risk for early menopause, (hazard ratio [HR] 1.70; 95%CI, 1.47-1.96), compared with women with cycles from 26 to 31 days. Women with menstrual cycles longer than or equal to 40 days had a lower risk for early natural menopause (HR 0.44; 95% CI, 0.34-0.58). Irregular cycle lengths were associated with lower risk for early menopause compared with regular cycle lengths (HR 0.51; 95% CI, 0.43-0.60).
Study investigators conclude, “In this study following 108,811 members of the [Nurses’ Health Study 2] for incident early menopause we observed risk to be strongly related to menstrual cycle length, regularity, and age at menarche. Taken together, these results are consistent with the rate of ovulation as a unifying mechanism for the associations observed. We adjusted for a wide range of diet, lifestyle and behavioral factors that may affect menstrual characteristics, however, determinants of cycle length and regularity and the etiology of these associations merit further consideration.”
Whitcomb BW, Purdue-Smithe A, Hankinson SE, Manson JE, Rosner BA, Bertone-Johnson ER. Menstrual cycle characteristics in adolescence and early adulthood are associated with risk of early natural menopause [published online July 27, 2018]. J Clin Endocrinol Metab. doi: 10.1210/jc.2018-01110