Short childbearing years bear increased hazard of insulin resistance

Women with short reproductive period are at higher risk of insulin resistance, a study has found.

Researchers looked at 3,327 middle-aged and older women (median age, 54 years) from the Korean Genome and Epidemiology Study. They evaluated insulin resistance and sensitivity using the homeostatic model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI). Reproductive years were categorized into four groups of 3-year incremental differences: Q1, <30 years; Q2, 30–32 years; Q3, 33–35 years; and Q4, >35 years.

The mean menarche age was 16.0 years, while the median menopause age was 49 years. Women in the lowest quartile of reproductive years had higher age and menarche age, whereas those in the highest quartile had the highest body mass index.

Linear mixed model for a repeated-measures covariance pattern showed that over a mean follow-up of 10.8 years, changes in HOMA-IR were significantly pronounced in the group of women with fewest reproductive years (Q1) than in the group of those with the most reproductive years (Q4; p=0.022).

Moreover, changes in QUICKI were significantly smaller in the group of women with fewest vs most reproductive years (p=0.048).

On Cox proportional hazards regression analysis, the hazard ratios for new-onset insulin resistance in comparison with the lowest quartile of reproductive years were 0.807 (95 percent confidence interval [CI], 0.654−0.994) in the second quartile, 0.793 (95 percent CI, 0.645−0.974) in the third quartile, and 0.770 (95 percent CI, 0.622−0.953) in the highest quartile.

The findings contribute to evidence indicating that reproductive factors may play a role in the development of diabetes in middle-aged and older women, the researchers said.