Parity and mortality in cases of childhood-onset diabetes mellitus

Aims: This study aims to assess the association between parity and mortality in adults with childhood-onset type 1 diabetes (T1D) and their matched controls. Methods: Individual data (308 617 person-years) on mortality and the reproductive histories of a Finnish cohort of 2307 women and 2819 men with T1D, each with two matched controls, were obtained from the National Population Register. All persons with diabetes had been diagnosed with T1D in 1965–1979 at the age of 17 or under. Results: All-cause mortality in people without offspring was significantly higher than that in people with children among both people with diabetes and non-diabetic control persons in both sexes (all p-values <0.01). In men with offspring, the decrease of mortality rate compared with men without offspring was less marked among those with diabetes (9% reduction in mortality hazard ratio (HR) with one offspring, 47% with two) than among those without diabetes (33% HR (p = 0.025) and 61% HR (p = 0.023) reduction, respectively). In women with offspring, the association between parity and mortality was independent of diabetes status. Having at least two offspring was associated with a decreased hazard of diabetes-related death regardless of sex; among women with diabetes, even having one offspring was associated with a decreased hazard of dying from diabetes (HR = 0.46; 95% CI 0.31, 0.69). Conclusions: The association between parity and mortality follows different patterns in men and women with T1D. To what extent this reflects effects of health on family planning decisions in people with T1D cannot be defined without further studies. Copyright © 2016 John Wiley & Sons, Ltd.