Researchers have discovered that children exposed in their home to secondhand smoke as toddlers were likelier to have higher BMI measurements and larger waists by age 10.

Researchers from the University of Montreal and its affiliate CHU Sainte Justine Research Centre were able to establish links between childhood obesity and exposure to smoking during the early years through their parents. Study lead Professor Linda Pagani said, however, that the effects they reported may be an underestimation because participating parents may have under-reported how much they smoked, out of embarrassment. The study was published in the Oxford University Press journal Nicotine and Tobacco Research.

Still, according to results, by the time the participating children that were exposed continuously or intermittently to smoke were 10 years old, they had BMI scores higher by 0.48 to 0.81 points and waists larger by up to three-fifths of an inch compared with children of the same age that were not exposed to secondhand smoke when they were toddlers.

"This prospective association is almost as large as the influence of smoking while pregnant," said Pagani.

Similar studies have been carried out before but the study Pagani led is the first to specifically identify the effects of smoke exposure to children's weights.

The researchers came to their conclusion by using data gathered via the Quebec Longitudinal Study of Child Development, a comprehensive survey involving children born in Quebec in which both parents and teachers contribute information regarding child development, social environment, lifestyle, well-being and behavior. By comparing information on 2,055 families, the researchers were able to determine the effects of smoke exposure on children.

According to Pagani, there may be several reasons behind how early exposure to smoke increases risks of obesity in children. One is that secondhand smoke may be causing endocrine imbalances, which alters neurodevelopmental functions at a crucial time that the hypothalamus is developing. This damages vital systems that are also still developing, leading to the effects reported by the researchers.

All over the world, it is estimated that 40 percent of children are exposed to secondhand smoke in their own homes. Children have higher ventilation requirements than adults for every kilogram of weight so given both are exposed to the same level of smoke, more noxious effects manifest in children.

The researchers hope the results of their study will encourage public health initiatives aimed at reducing smoke exposure to children during their early years.

Caroline Fitzpatrick and Danny Nguyen also contributed to the study.

Photo: Joriz De Guzman | Flickr

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