Abstract
Increased mortality has been observed in mothers and fathers with male offspring but little is known regarding specific diseases. In a register linkage we linked women born 1925–1954 having survived to age 50 (n = 661,031) to offspring and fathers (n = 691,124). Three approaches were used: 1) number of total boy and girl offspring, 2) sex of the first and second offspring and 3) proportion of boys to total number of offspring. A sub-cohort (n = 50,736 mothers, n = 44,794 fathers) from survey data was analysed for risk factors. Mothers had increased risk of total and cardiovascular mortality that was consistent across approaches: cardiovascular mortality of 1.07 (95% CI: 1.03–1.11) per boy (approach 2), 1.04 (1.01–1.07) if the first offspring was a boy, and 1.06 (1.01–1.10) if the first two offspring were boys (approach 3). We found that sex of offspring was not associated with total or cardiovascular mortality in fathers. For other diseases or risk factors no robust associations were seen in mothers or fathers. Increased cardiovascular risk in mothers having male offspring suggests a maternal disease specific mechanism. The lack of consistent associations on measured risk factors could suggest other biological pathways than those studied play a role in generating this additional cardiovascular risk.
Highlights
MethodsWe included only those groups where we had information on the full reproductive age of mothers from 15 to 50 years and with follow-up of death afterwards
Increased mortality has been observed in mothers and fathers with male offspring but little is known regarding specific diseases
There is some supporting evidence in other studies: In non-human mammals, such as the Red Deer, maternal investment is often greater in male than in female offspring, which may provide an evolutionary advantage as the chance of reproduction for males depends on maternal investment[17]
Summary
We included only those groups where we had information on the full reproductive age of mothers from 15 to 50 years and with follow-up of death afterwards. This gave 1,936,257 offspring with 784,325 mothers and 786,262 fathers We analysed those with complete data on covariates giving 661,013 women and 691,124 men. The parents were linked to their offspring and to the Cause of Death Registry, the Cancer Registry, Statistics Norway and from the Cohort of Norway (CONOR)[28]. We investigated CVD and all-cause mortality in mothers having offspring with twins, perinatal deaths, pre-eclampsia and with different length of inter-pregnancy intervals, and we investigated CVD mortality in the CONOR sub-cohort. The study is part of the study “Inter- and intra-generational transmission of risk” was approved by the Norwegian Regional Ethics Committee, No 2010/260
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
