Study Title:

Childhood Obesity and Premature Death

Study Abstract

Background The effect of childhood risk factors for cardiovascular disease on adult mortality is poorly understood.

Methods In a cohort of 4857 American Indian children without diabetes (mean age, 11.3 years; 12,659 examinations) who were born between 1945 and 1984, we assessed whether body-mass index (BMI), glucose tolerance, and blood pressure and cholesterol levels predicted premature death. Risk factors were standardized according to sex and age. Proportional-hazards models were used to assess whether each risk factor was associated with time to death occurring before 55 years of age. Models were adjusted for baseline age, sex, birth cohort, and Pima or Tohono O'odham Indian heritage.

Results There were 166 deaths from endogenous causes (3.4% of the cohort) during a median follow-up period of 23.9 years. Rates of death from endogenous causes among children in the highest quartile of BMI were more than double those among children in the lowest BMI quartile (incidence-rate ratio, 2.30; 95% confidence interval [CI], 1.46 to 3.62). Rates of death from endogenous causes among children in the highest quartile of glucose intolerance were 73% higher than those among children in the lowest quartile (incidence-rate ratio, 1.73; 95% CI, 1.09 to 2.74). No significant associations were seen between rates of death from endogenous or external causes and childhood cholesterol levels or systolic or diastolic blood-pressure levels on a continuous scale, although childhood hypertension was significantly associated with premature death from endogenous causes (incidence-rate ratio, 1.57; 95% CI, 1.10 to 2.24).

Conclusions Obesity, glucose intolerance, and hypertension in childhood were strongly associated with increased rates of premature death from endogenous causes in this population. In contrast, childhood hypercholesterolemia was not a major predictor of premature death from endogenous causes.

From press release:

In a study published in The New England Journal of Medicine, Associate Professor Paul Franks of Umeå University in Sweden, in collaboration with researchers in the US, shows how childhood obesity, together with other risk factors for cardiovascular disease, affects premature death.

The researchers studied 4,857 children from the indigenous Indian population in the US, born between 1945 and 1984. All underwent detailed medical examinations, including measurement of body fat (BMI), cholesterol, blood pressure, and blood sugar. The children were then followed up for an average of 24 years of their continuing lives, during which time further parameters were monitored, as were any deaths in the group.

In this group, 559 individuals (11.5%) died before the age of 55, 166 of them from natural causes. The most common natural causes of death were alcohol-related liver disease and cardiovascular disease. Among the four risk factors that were monitored in the study, childhood obesity turned out to be the strongest predictor of premature death from disease. The 1,214 most overweight children in the group (the upper quarter) had a mortality frequency that was more than twice as high (230%) of that of the leanest quarter of those studied.

In a similar manner, high blood sugar was shown to elevate the frequency of death by 73%, and high blood pressure in the childhood years raised the risk by 53%. These two risk factors were almost entirely associated with the degree of obesity. On the other hand, the scientists found no measurable effects on mortality from high cholesterol values in childhood. All children in the group were diabetes free when the study commenced, but nearly 600 of them developed diabetes during the follow-up period. However, this fact could not explain the connection between childhood obesity and premature death.

This is the first study of its kind and is especially interesting since the group under study, as children as early as the 1940s, had an equally high level of obesity as many children today. The proportion of overweight children is on the rise all over the world, and the authors conclude that measure to increase physical activity, improve food habits, and keep families together should receive high priority during early childhood.

Paul Franks collaborated in the study with researchers at the National Institutes of Diabetes and Digestive and Kidney Disease (NIDDK) and Mount Sinai School of Medicine, New York, both in the US.

Study Information

PW Franks, RL Hanson, WC Knowler, ML Sievers, PH Bennett, HC Looker.
Childhood Obesity, Other Cardiovascular Risk Factors, and Premature Death.
New England Journal of Medicine
2010 February
Diabetes Epidemiology and Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ.

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