Understanding the causes and consequences of childhood obesity

Childhood obesity is on the rise in Nova Scotia. “A third of grade five students in Nova Scotia were overweight or obese in 2011,” says Dr. Stefan Kuhle, a PERU epidemiologist who’s exploring the root causes, current consequences and future costs of the childhood obesity epidemic. “Compared to 2003, just as many were overweight, and more were obese, in 2011.”
 

Dr. Kuhle is working with Dalhousie University-IWK colleague Dr. Sara Kirk and University of Alberta researcher Dr. Paul Veugelers to analyze data collected through the Children’s Lifestyle And School performance Study, which surveyed 5,000 Nova Scotia grade five students in 2003 (CLASS I) and again in 2011 (CLASS II), about their food intake, physical activity levels and health, including BMI. New questions added in 2011 about sleep and academic performance will shed light on the links between sleep, obesity, activity, nutrition, general health, and learning.
 
In addition to analyzing the children’s data, Drs. Kuhle and Veugelers have linked it to the Nova Scotia Atlee Perinatal Database to see what maternal and perinatal factors may contribute to the rising rates of childhood obesity. “We found that maternal weight is the strongest determinant of childhood obesity,” says Dr. Kuhle. “Children of obese mothers are four times more likely to be obese than peers born of normal-weight mothers.” This association has serious implications for Nova Scotia, where the researchers have found that 46 per cent of women are overweight or obese at the beginning of their pregnancy and 60 per cent gain more weight in pregnancy than national guidelines recommend.
 
The impact of obesity on children’s health – now and in the future – is enormous. By linking the 2003 children’s health data to administrative health records, Dr. Kuhle has found that overweight and obese children have higher rates of asthma and other respiratory disorders, middle ear infections, mood disorders, and other health problems – and that they see their doctors and go to the hospital more often than their healthy-weight peers. In their analysis of the Canadian Health Measures Survey, he and colleagues at the University of Alberta found higher levels of such disease markers as cholesterol, triglycerides and C-reactive protein in overweight and obese children.
 
If they’re having health problems now, how does the future bode for overweight and obese children? Dr. Kuhle is co-supervising Mark Staples, a student from Dalhousie University's Department of Industrial Engineering, to create a model that’s mapping the trajectories of weight status in Canadians up to 15 years into the future. “We need to show policymakers what the impacts will be if the current trend continues,” says Dr. Kuhle. “We need to show how investing in prevention now will pay dividends in the future.”
 
It’s crucial, however, to identify what prevention strategies work best. To that end, Dr. Kuhle is helping Dr. Kirk evaluate the impact of a health-promoting schools initiative in southwestern Nova Scotia. “We want to learn what factors have the greatest influence on creating a school culture that embraces healthy behaviours,” he says, noting that school-based initiatives are just part of the equation. “We need to include families and communities in a comprehensive effort to reverse the obesity epidemic.”