Date Published: 2 April 2014
Young smokers father fatter sons
Recent research as part of the 'Children of the 90s' study indicates that, on average, the teenage sons of men who started smoking frequently before the age of 11 years have more body fat than their peers e.g. school friends. This study, which highlights a link between smoking and obesity, was carried out by scientists based in Bristol and London (England, UK).
Specifically, the study found that men who started smoking regularly before the age of 11 had sons who, on average, had 5-10kg more body fat than their peers by the time they reached their teenage years (13-19 years old). The researchers suggest that this might mean that exposure to tobacco smoke before the start of puberty may lead to metabolic* changes in the next generation. *What is Metabolism?
What about daughters?
Although the same general trend applied to daughters, the researchers did not find as marked an effect on the body fat of daughters of the men who started smoking at such a young age. Many other factors, such as genetic factors and the father's weight, were taken into account but none could explain the higher than average body fat of the sons of the men who started smoking before the age of 11 years. Despite the higher body fat recorded for their sons, the fathers who started smoking before 11 tended to have lower BMIs (body mass index) on average.
What about men who started smoking slightly later?
The effect was not found in the sons of men who started smoking after the age of 11. This has been interpreted as suggesting that the duration of time before the onset of puberty is a particularly sensitive time for environmental exposures. This view is consistent with a prior hypothesis by the authors based on earlier Swedish studies that linked paternal ancestor's food supply in mid childhood with mortality rates in grandchildren.
The scale of the study
Fathers: 9,886 fathers were enrolled in the study, of which 5,376 (54%) had been smokers at some time in their lives. Of these, 166 (only 3%) said that they started smoking regularly before the age of 11 years.
Sons: The sons of the 9,886 fathers were measured at the ages of 13, 15 and 17.
On average, the sons of the men who started smoking before they were 11 years old had higher BMIs at each of the time points of 13, 15 and 17 years old than the sons of men who had started smoking later or who had never smoked. Specifically, the sons of the of men in the study who started smoking before the age of 11 had significantly higher levels of fat mass (recorded using whole-body scans), ranging from an extra 5kg to 10kg between ages 13 and 17.
Professor Marcus Pembrey, one of the authors of the study, said:
" This discovery of trans-generational effects has big implications for research into the current rise in obesity and the evaluation of preventative measures. It is no longer acceptable to just study lifestyle factors in one generation. We are probably missing a trick with respect to understanding several common diseases of public health concern by ignoring the possible effects of previous generations."
Professor David Lomas, Chair of the Medical Research Council (MRC)'s Population and Systems Medicine Board, added:
" Population studies have provided a wealth of information about health and disease, including first identifying the link between smoking and cancer more than 60 years ago. This research clearly demonstrates that such studies have so much more to give, which is why it's vital that the future potential of cohorts and the studies they make possible is not jeopardised by the proposed EU data regulations."
University, England (UK)