The associations between nationality, fertility history and diabetes-related mortality: a retrospective cohort study in the Brussels-Capital Region (2001-2005)

Background The relationship between women's parity and diabetes mortality has been investigated in several studies, with mixed results. This study aims to establish if parity and age at first birth are associated with diabetes-related mortality and if these factors contribute to variations in diabetes-related mortality among women with different nationalities.

Methods Data of the 2001 census are linked to registration records of all deaths and emigrations (period 2001-2005). The study population comprises all female inhabitants of the Brussels-Capital Region aged 45-74 of either Belgian or North African nationality (n = 108 296). Age-standardized mortality rates (direct standardization) and mortality rate ratios (Poisson's regression) are computed.

Results Both parity and age at first birth are associated with diabetes-related mortality. Highest risks of dying from diabetes are observed among grandmultiparous women and teenage mothers. Differences in diabetes-related mortality according to nationality are observed. Age-standardized diabetes mortality rates are higher in North African [ASMR = 417.4/100 000; 95% confidence interval (CI) 227.2-607.7] than in Belgian women (ASMR = 184.0/100 000; 95% CI 157.3-210.8). Taking parity, age at first birth and education into account, these differences largely disappear.

Conclusions Reproductive factors are associated with diabetes-related mortality and play an important part in the higher diabetes-related mortality of North African compared with Belgian women.