Differential transmission of type 1 diabetes from diabetic fathers and mothers to their offspring.
We studied the incidence of type 1 diabetes in the offspring of patients with childhood- and adolescent-onset type 1 diabetes and several risk factors predicting the risk. We defined the diabetes status in the offspring of all probands who were included in the nationwide register of Finnish type 1 diabetic patients diagnosed at the age of < or =17 years from 1965 to 1979. A total of 5,291 offspring at risk contributed 72,220 person-years of follow-up between 1970 and 2003. Of them, 259 offspring developed type 1 diabetes by the end of 2003, giving a cumulative incidence of 6.7% (95% CI 5.9-7.5) by the age of 20 years. The incidence of type 1 diabetes in the offspring between the years 1980 and 2003 was 35.3, 44.6, and 44.6 per 10,000 person-years for the age-groups 0-4, 5-9, and 10-14 years, respectively. Poisson regression analyses showed a marked increase in incidence of 5.3% per year from 1983 to 2003. The greatest increase occurred in the youngest offspring, aged 0-4 years. Of the offspring of male probands, 7.8% were affected by the age of 20 years compared with 5.3% of the offspring of female probands (relative risk 1.7 [95% CI 1.3-2.2]). The young age at onset of diabetes increased the risk of type 1 diabetes in the offspring of diabetic fathers but not in the offspring of diabetic mothers. In conclusion, our findings revealed that in the offspring of type 1 diabetic patients, the increase in the recurrence risk of type 1 diabetes was not more rapid compared with that in the background population. In the multivariate analyses, statistically significant predictors of type 1 diabetes in the offspring were male sex of the diabetic parent, young age at diagnosis in the male parent, and the more recent year of birth of the offspring.
Harjutsalo
Valma
V
National Public Health Institute, Mannerheimintie 166, FIN-00300 Helsinki, Finland. valma.harjutsalo@ktl.fi
Reunanen
Antti
A
Tuomilehto
Jaakko
J
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology* / Q000235:genetics*; D005220:Fathers; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D009035:Mothers; D015999:Multivariate Analysis; D009679:Nuclear Family