Ruth Morley1, Janet McCalman, John B Carlin. 1. Clinical Epidemiology and Biostatistics Unit, University of Melbourne Department of Paediatrics, and Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Australia. morleyr@unimelb.edu.au
Abstract
BACKGROUND: The widely observed association between birth size and risk of later coronary heart disease (CHD) has not been examined in an impoverished pre-20th century birth cohort. METHODS: Birth weights and maternal characteristics, for births between 1857 and 1900 in a charity hospital, were recorded from preserved ledgers. Names were linked to death certificates to determine age and cause of death. Death with CHD was coded using specific criteria, and survival analysis methods were used to relate risk of CHD to birth weight, allowing for competing causes of death and adjusting for potentially confounding maternal factors. RESULTS: Death certificates were traced for 8,584 (53%) of 16,272 registered live-births. Survival analyses were confined to 2,938 subjects (1,572 male, 1,366 female) who survived beyond age 40, since none of the 486 CHD cases was recorded earlier. CHD risk increased with time, but there was no evidence that it was related to birth weight, in men or women. CONCLUSIONS: We did not replicate findings in more recent cohorts. This may represent a true lack of association in a historical cohort who we believe remained impoverished through their early life. However, we acknowledge the strong possibility of misclassification of cause of death by the person filling in the death certificate and/or our coding criteria, and temporal change in diagnostic criteria for CHD. We cannot exclude the possibility that low birth weight babies 'programmed' in utero for later CHD were more likely to die in infancy, in this cohort with a high infant mortality rate.
BACKGROUND: The widely observed association between birth size and risk of later coronary heart disease (CHD) has not been examined in an impoverished pre-20th century birth cohort. METHODS: Birth weights and maternal characteristics, for births between 1857 and 1900 in a charity hospital, were recorded from preserved ledgers. Names were linked to death certificates to determine age and cause of death. Death with CHD was coded using specific criteria, and survival analysis methods were used to relate risk of CHD to birth weight, allowing for competing causes of death and adjusting for potentially confounding maternal factors. RESULTS:Death certificates were traced for 8,584 (53%) of 16,272 registered live-births. Survival analyses were confined to 2,938 subjects (1,572 male, 1,366 female) who survived beyond age 40, since none of the 486 CHD cases was recorded earlier. CHD risk increased with time, but there was no evidence that it was related to birth weight, in men or women. CONCLUSIONS: We did not replicate findings in more recent cohorts. This may represent a true lack of association in a historical cohort who we believe remained impoverished through their early life. However, we acknowledge the strong possibility of misclassification of cause of death by the person filling in the death certificate and/or our coding criteria, and temporal change in diagnostic criteria for CHD. We cannot exclude the possibility that low birth weight babies 'programmed' in utero for later CHD were more likely to die in infancy, in this cohort with a high infant mortality rate.
Authors: Zhenghe Wang; Zhiyong Zou; Zhongping Yang; Yanhui Dong; Jieyun Song; Bin Dong; Jun Ma; Luke Arnold Journal: BMC Public Health Date: 2018-10-26 Impact factor: 3.295