Aim: T2D develops in the genetically susceptible in response to environmental changes such as obesity, sedentarism and unhealthy diets. However, factors during fetal life may also influence susceptibility to T2D. In animal studies, vitamin-A deficiency has been associated with impaired fetal pancreatic development and increased risk of developing T2D, but until now, no human studies have explored if low gestational vitamin-A increases the risk of adult T2D. Thus, the present study aimed to determine if offspring of mothers, who were exposed to extra vitamin-A from food fortification during pregnancy, had lower risk of developing adult T2D than offspring of mothers exposed to less vitamin-A.
Method: In 1962, Danish mandatory margarine fortification with vitamin-A was increased by 25%. We examined individual risk of developing T2D until midlife, where the date of diagnosis was retrieved from National Diabetes Registries, among all individuals (n=193,803) born within two years before (1st September 1959-31st December 1960) and within two years after (1st December 1962-31st March 1964) the policy change to the mandatory vitamin-A fortification, e.g. exposed to either higher or lower vitamin-A during gestation.
Results: Among exposed, 1,273 developed T2D; among less-exposed 1,322 developed T2D. Cox-regression analysis showed that the individuals exposed to higher vitamin-A were less likely to develop T2D than individuals exposed to lower levels: HR=0·88; 95%CI: 0·81-0·95 (p=0·001).
Conclusion: Knowledge about modifiable factors of importance for the primary prevention of T2D is imperative, and this study shows that fetal exposure to extra vitamin-A added to margarine may reduce T2D-risk until mid-life by about 14%. These results are relevant for General Practice/Family Medicine being the first contact with the pregnant mother, and often consulting with women before they conceive. This study also has public health relevance and demonstrates potential benefit of a simple societal intervention using food supplementation with vitamin-A for risk of developing T2D, one of today’s most costly chronic diseases.