[Markers for risk of IDDM in children of Danish patients with IDDM. A population-based, historical prospective study]. / Markører for IDDM-risiko hos børn af danske IDDM-patienter. En populationsbaseret, historisk prospektiv undersøgelse.

To assess the offspring IDDM recurrence risk in a Danish population-based study and to investigate parental and offspring related biological variables that might influence this risk, we identified 2726 IDDM probands and their 2826 offspring from a background population of 1.725 million people (33% of the Danish population). Proband current age was 20-60 years and age at IDDM onset was 30 years or less. Offspring data were obtained by a questionnaire. The cumulative IDDM risk up to age 30 years was found significantly decreased in maternal offspring compared to paternal offspring (2.3 +/- 0.6% and 5.7 +/- 0.9%, RR = 2.40, 95% CI 1.30-4.47; Mantel Cox: p = 0.004) only if parents were diagnosed with IDDM before offspring birth. However, due to a low number of diabetic offspring of probands diagnosed with IDDM after offspring birth, this observation need to be confirmed in a larger population. Using the Cox proportional hazards model we found that among several biological variables tested separately on offspring of male and female probands, all diagnosed with IDDM before pregnancy, paternal age at IDDM onset was the only statistically significant predictor of IDDM risk in offspring. Our findings may be important for counselling families in which one parent has IDDM.

Predictors of IDDM recurrence risk in offspring of Danish IDDM patients. Danish IDDM Epidemiology and Genetics Group.

It has previously been observed that offspring of mothers with insulin-dependent diabetes mellitus (IDDM) have a lower risk of IDDM than offspring of IDDM affected fathers. To assess the offspring IDDM recurrence risk in a Danish population-based study and to investigate parental and offspring-related biological variables that might influence this risk, we identified 2726 IDDM probands and their 2826 offspring from a background population of 1.725 million people (33% of the Danish population). Current age of probands was 20-65 years and their age at IDDM onset was 30 years or less. Sixty-nine offspring (2.4%) were affected with IDDM. The sex difference in the parental-offspring IDDM transmission rate was confirmed. The cumulative IDDM risk up to age 30 years was found to be significantly decreased in maternal offspring compared to paternal offspring (2.3 +/- 0.6 and 5.7 +/- 0.9 %, RR = 2.40, 95% CI 1.30-4.47; p = 0.004) only if parents were diagnosed with IDDM before birth of the offspring. However, due to the low number of diabetic offspring of probands diagnosed with IDDM after offspring birth, this observation needs to be confirmed in a larger population. In a subpopulation of the 2380 offspring, whose parents were all diagnosed with IDDM before offspring birth, the recurrence risk was significantly increased in offspring of male probands diagnosed up to age 17 years compared to offspring of fathers diagnosed at older ages (8.5 +/- 1.8 and 3.6 +/- 1.0%; RR = 2.27, 95% CI 1.21-4.25; p = 0.006). No such relation was found in maternal offspring. Using the Cox proportional hazards model on this offspring subpopulation we found that paternal age at IDDM onset was the only statistically significant predictor of IDDM recurrence risk. Our findings may be important for counselling families in which one parent has IDDM.