In a new study, study, published in May 2020 in the British Medical Journal, researchers at the University of Bristol used genetic data from nearly half a million people in the United Kingdom (UK) to determine how a person’s body size during childhood and early adulthood influenced the risk of developing heart disease and type 2 diabetes later in life. To do this, the researchers asked participants to recall what their body size was at age 10, and then compared that with their current body mass index (BMI) as an adult; the average age of the participants was 57. To rule out other contributing factors, the team used a technique called Mendelian randomization, which allows scientists to separate different factors that contribute to a disease and study a single facet, such as body size or weight, independent of other factors that could contribute to the same disease, such as air pollution. While other research has linked being overweight as a child with the development of heart disease and type 2 diabetes later on in life, the new study concluded that the association between childhood obesity and the risk of coronary artery disease (CAD) and type 2 diabetes is not solely a result of being overweight as a child. Instead, it’s a result of a person carrying excess fat into adulthood. “Individuals who are overweight as children tend to remain overweight as adults, making them more at risk of these health outcomes,” says Tom Richardson, PhD, a UKRI innovation research fellow in genetic epidemiology at the University of Bristol in England, who led the study. The new research suggests that losing weight through diet and exercise creates, “a window of opportunity between childhood and adulthood to mitigate the effect of childhood obesity on disease risk,” Dr. Richardson explains. At exactly what ages this window of possibility exists is still a mystery because of the limited amount of information the researchers collected during the study, as well as potential inaccuracies with recalled childhood body size. In their next phase of research, Richardson says his team will try to pinpoint a certain age by which an obese person should change their health habits to have the best shot at lowering their risk for obesity-related disease in the long term. Based on the data we do have, the sooner a person can shed excess fat, the better. “Being overweight over many years increases risk of coronary heart disease and type 2 diabetes, so it is plausible that reducing excess weight as early in life as possible will best mitigate disease risk,” he says. RELATED: Why Are Healthy Eating Habits Important?
Early Intervention
According to Francine Erenberg, MD, a pediatric cardiologist at the Cleveland Clinic in Ohio, there are a number of reasons why childhood obesity is linked with heart disease later in life. “Heart disease does have its seeds in adolescence. It could be due to the things that go along with being overweight or obese, such has having high blood pressure and cholesterol and potentially living a more sedentary lifestyle, which are all risk factors for heart disease later in life,” says Dr. Erenberg. While a person may be genetically predisposed to certain conditions, the new research suggests that managing risk factors during teenage years or early adulthood that are in your control, including shedding extra body weight, could help reduce a person’s risk of developing even conditions they’re genetically predisposed to, says Erenberg, who uses high cholesterol as an example. “You can’t change the gene that causes it, but you can mitigate high cholesterol with medication and lifestyle habits,” she says, noting that while statins, which are commonly used to treat high cholesterol in the United States, are approved for children as young as 8 years old, the medication is typically reserved for severe cases. “With the exception of very young children — there should be no restriction of fats in less-than-2-year-olds — diet modification with an eye toward healthy eating and portion control can start during childhood, and may help kids understand and develop good eating habits,” says Erenberg. “Similarly, exercise and an active lifestyle can start at a young age, and habits developed when young may influence our habits as children get older.” Type 2 diabetes is another gray area where both obesity and genetics may work in tandem. A study published in April 2020 in Diabetologia found that while genetic predisposition doubled a person’s chances of developing type 2 diabetes, being obese increased the risk eightfold. According to the United States’ National Institutes of Health, high blood sugar from diabetes can damage the blood vessels over time as well as the nerves that control your heart, increasing your risk of heart attack and stroke. In addition to addressing diseases that a person is genetically predisposed to, maintaining a healthy weight early in life through aerobic exercise and by cutting out refined sugars, processed foods, fried foods, and simple carbohydrates such as cereal, and instead eating a primarily plant-based diet that’s rich in fruits and vegetables, is key to reducing your risk of both type 2 diabetes and cardiovascular disease in the long term, Erenberg suggests. “If we focus on these issues during the teenage years rather than once a person is an adult, we may be able to change the natural history of what a person’s health will look like by middle age,” says Erenberg. “Because by then, it’s often too late to change outcomes.”
