Major cardiovascular events and death in parents of children with type 1 diabetes: a register-based matched cohort study in Sweden.

Aims/hypothesis: Parenting a child with type 1 diabetes has been associated with stress-related symptoms. This study aimed to elucidate the potential impact on parental risk of major cardiovascular events (MCE) and death.

Methods: In this register-based study, we included the parents of 18,871 children, born 1987-2020 and diagnosed with type 1 diabetes in Sweden at <18 years. The median parental age at the child's diagnosis was 39.0 and 41.0 years for mothers and fathers, respectively. The cohort also encompassed 714,970 population-based matched parental control participants and 12,497 parental siblings. Cox proportional hazard regression models were employed to investigate the associations between having a child with type 1 diabetes and incident MCE and all-cause death, and, as secondary outcomes, acute coronary syndrome and ischaemic heart disease (IHD). We adjusted for potential confounders including parental type 1 diabetes and country of birth.

Results: During follow-up (median 12 years, range 0-35), we detected no associations between parenting a child with type 1 diabetes and MCE in mothers (adjusted HR [aHR] 1.02; 95% CI 0.90, 1.15) or in fathers (aHR 1.01; 95% CI 0.94, 1.08). We noted an increased hazard of IHD in exposed mothers (aHR 1.21; 95% CI 1.05, 1.41) with no corresponding signal in fathers (aHR 0.97; 95% CI 0.89, 1.05). Parental sibling analysis did not confirm the association in exposed mothers (aHR 1.01; 95% CI 0.73, 1.41). We further observed a slightly increased hazard of all-cause death in exposed fathers (aHR 1.09; 95% CI 1.01, 1.18), with a similar but non-significant estimate noted in exposed mothers (aHR 1.07; 95% CI 0.96, 1.20). The estimates from the sibling analyses of all-cause death in fathers and mothers were 1.12 (95% CI 0.90, 1.38) and 0.73 (95% CI 0.55, 0.96), respectively.

Conclusions/interpretation: Having a child diagnosed with type 1 diabetes in Sweden was not associated with MCE, but possibly with all-cause mortality. Further studies are needed to disentangle potential underlying mechanisms, and to investigate parental health outcomes across the full lifespan.