…may be smaller than previously thought for many chronic conditions. A paper by Thompson (2014) uses data from 125,000 parent-child pairs to determine that:
children with a parent who has a specific chronic health condition are at least 100% more likely to have the same condition themselves. To assess the role of genetic mechanisms in generating these strong correlations, I estimate models using a sample of approximately 2,400 adoptees, and find that genetic transmission accounts for only 20%-30% of the baseline associations.
Could adoption itself play a role in the reduce transmission of chronic diseases? Additional evidence seems to discount this claim:
to corroborate these adoptee-based estimates, I examine health correlations among monozygotic twins, which provide an upper bound estimate of genetic influences, and find a similarly modest role for genetic transmission
The modest role of genetics in the incidence of chronic conditions may be due to a number of factors. For instance, many chronic conditions appear or are exacerbated by lifestyle considerations such as patient diet and exercise habits. Additionally, the prevalence of chronic conditions is increasing as medical advances both decrease the health impact of many acute diseases and increase longevity for people who have chronic diseases.
- Owen Thompson. Genetic Mechanisms in the Intergenerational Transmission of Health. Journal of Health Economics Available online 11 March 2014.