Weight Change and Accumulation of Chronic Conditions in Women During Reproductive Years.

Objective: We examined the association between BMI change and risk of multimorbidity among women of reproductive age and estimated annual weight gain before and after diagnosis of chronic conditions.

Methods: Data were from 8895 women in the Australian Longitudinal Study on Women's Health who had no chronic conditions at baseline. BMI from Survey 1 (ages 18-23) and Survey 3 (ages 25-30) defined BMI change categories. Linear mixed models estimated annual weight gain from Survey 1 to Survey 9 (ages 43-49).

Results: Compared to stable normal BMI, stable obesity and increasing BMI were associated with a higher risk of incident multimorbidity (OR = 1.79 [95% CI: 1.11, 2.90] and 1.34 [1.10, 1.63]). Women who remained free of chronic conditions gained 0.50 kg (0.48, 0.52) annually. Women with one condition gained 0.54 kg (0.52, 0.56): 0.55 (0.53, 0.57) before and 0.54 (0.51, 0.57) after diagnosis. Those with multimorbidity gained 0.65 kg (0.63, 0.67): 0.75 kg (0.70, 0.80) before the first, 0.60 kg (0.56, 0.64) between the first and second, and 0.57 kg (0.53, 0.61) after the second condition.

Conclusions: Although weight gain declined after diagnosis, it remained higher than among women without conditions, underscoring the need for improved post-diagnosis weight management.