Do changes in sex steroid hormones precede or follow increases in body weight during the menopause transition? Results from the Study of Women's Health Across the Nation

Abstract

Context: Whether menopause-related changes in sex steroids account for midlife weight gain in women or whether weight drives changes in sex steroids remains unanswered.

Objective: The objective of the study was to characterize the potential reciprocal nature of the associations between sex hormones and their binding protein with waist circumference in midlife women.

Design, setting, and participants: The study included 1528 women (mean age 46 yr) with 9 yr of follow-up across the menopause transition from the observational Study of Women's Health Across the Nation.

Main outcome measures: Waist circumference, SHBG, testosterone, FSH, and estradiol were measured.

Results: Current waist circumference predicted future SHBG, testosterone, and FSH but not vice versa. For each SD higher current waist circumference, at the subsequent visit SHBG was lower by 0.04-0.15 SD, testosterone was higher by 0.08-0.13 SD, and log(2) FSH was lower by 0.15-0.26 SD. Estradiol results were distinct from those above, changing direction across the menopause transition. Estradiol and waist circumference were negatively associated in early menopausal transition stages and positively associated in later transition stages (for each SD higher current waist circumference, future estradiol was lower by 0.15 SD in pre- and early perimenopause and higher by 0.38 SD in late peri- and postmenopause; P for interaction <0.001). In addition, they appeared to be reciprocal, with current waist circumference associated with future estradiol and current estradiol associated with future waist circumference. However, associations in the direction of current waist circumference predicting future estradiol levels were of considerably larger magnitude than the reverse.

Conclusions: These Study of Women's Health Across the Nation data suggest that the predominant temporal sequence is that weight gain leads to changes in sex steroids rather than vice versa.

Fig. 1.

Sequential relationships between waist circumference and SHBG using standardized estimates. Red arrows, Association between current waist circumference and future SHBG level; Blue arrows, association between current SHBG level and future waist circumference; black arrows, top association between current SHBG and future SHBG; bottom association between current waist circumference and future waist circumference. Solid lines indicate statistically significant associations, whereas dashed lines indicate nonsignificant associations. *, P < 0.05; **, P < 0.01; ***, P < 0.001. The thickness of the arrow corresponds to the magnitude of the association (i.e. thicker arrows mean a larger effect size). Values provided are standardized regression estimates. Visit 3 occurred 3 yr after baseline; visit 6 occurred 6 yr after baseline; and visit 9 occurred 9 yr after baseline.

Fig. 2.

Sequential relationships between waist circumference and T using standardized estimates. Red arrows, Association between current waist circumference and future SHBG level; blue arrows, association between current SHBG level and future waist circumference; black arrows, top association between current SHBG and future SHBG; bottom association between current waist circumference and future waist circumference. Solid lines indicate statistically significant associations, whereas dashed lines indicate nonsignificant associations. *, P < 0.05; **, P < 0.01; ***, P < 0.001. The thickness of the arrow corresponds to the magnitude of the association (i.e. thicker arrows mean a larger effect size). Values provided are standardized regression estimates. Visit 3 occurred 3 yr after baseline; visit 6 occurred 6 yr after baseline; and visit 9 occurred 9 yr after baseline.

Fig. 3.

Sequential relationships between waist circumference and FSH using standardized estimates. Red arrows, Association between current waist circumference and future SHBG level; blue arrows, association between current SHBG level and future waist circumference; black arrows, top association between current SHBG and future SHBG; bottom association between current waist circumference and future waist circumference. Solid lines indicate statistically significant associations, whereas dashed lines indicate nonsignificant associations. *, P < 0.05; **, P < 0.01; ***, P < 0.001. The thickness of the arrow corresponds to the magnitude of the association (i.e. thicker arrows mean a larger effect size). Values provided are standardized regression estimates. Visit 3 occurred 3 yr after baseline; visit 6 occurred 6 yr after baseline; and visit 9 occurred 9 yr after baseline.

Fig. 4.

Sequential relationships between waist circumference and estradiol, stratified by menopausal status using standardized estimates. A, Premenopausal and early perimenopausal women. B, Late perimenopausal and postmenopausal women. Red arrows, Association between current waist circumference and future SHBG level; blue arrows, association between current SHBG level and future waist circumference; black arrows, top, association between current SHBG and future SHBG; bottom association between current waist circumference and future waist circumference. Solid lines indicate statistically significant associations, whereas dashed lines indicate nonsignificant associations. *, P < 0.05; **, P < 0.01; ***, P < 0.001. The thickness of the arrow corresponds to the magnitude of the association (i.e. thicker arrows mean a larger effect size). Values provided are standardized regression estimates. Visit 3 occurred 3 yr after baseline; visit 6 occurred 6 yr after baseline; and visit 9 occurred 9 yr after baseline.