Paternal age and twinning in the Jerusalem Perinatal Study☆
Received 1 November 2007; received in revised form 28 June 2008; accepted 23 July 2008. published online 26 August 2008.
Abstract
Objective
To investigate whether incidence of twin deliveries is related to father's age, independently of mother's age, and whether it differs for same-sex or opposite-sex twin sets.
Study design
In a program of research on effects of paternal age, this study used data from a prospective cohort of 92,408 offspring born in Jerusalem from 1964 to 1976. Of the 91,253 deliveries in the Jerusalem Perinatal Study, 1115 were twin deliveries. The data were analyzed with General Estimate Equations to inform unconditional logistic regression.
Results
After controlling for maternal age, odds ratios (ORs) and 95% confidence intervals (95% CI) associated with father's ages 25–34 and 35+ were 1.3 (1.1, 1.7) and 1.5 (1.2, 2.1) respectively, compared with fathers <25 years old. The effect of maternal age was partly explained by paternal age. The ORs for opposite-sex twin sets and male–male twin sets increased slightly with paternal age, while the OR for same-sex and female–female twin decreased.
Conclusion
Studies of twins are used to estimate effects of genes and environment in a variety of diseases. Our findings highlight the need to consider paternal as well as maternal age when analyzing data on twins to explore etiology of diseases.
aDepartment of Psychiatry, New York University School of Medicine, NY, United States
bHebrew University-Hadassah Braun School of Public Health and Social Medicine, Jerusalem, Israel
cDepartment of Psychiatry, Columbia College of Physicians and Surgeons, NY, United States
Corresponding author at: Department of Psychiatry, New York University School of Medicine, Millhauser Labs, Room HN323, New York, NY 10016-6481, United States. Tel.: +1 212 263 6216; fax: +1 212 263 5717.
☆ Supported by NIH Grants: # 2R01 CA080971 (S. Harlap) and # 1R01 MH059114 (D. Malaspina) and the NARSADs (DM, SH, MP).
ABSTRACT