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Fat children have high cardiovascular risks as teens

Children who maintain a high BMI likely to have high heart risk at 15-16

Louise Prime

Friday, 26 November 2010

Children aged 9-12 who have a high body mass index (BMI) and fail to lose their excess weight are more likely than peers of a healthy weight to have risk factors for cardiovascular disease by the time they reach 15-16 years, a prospective cohort study has shown. Losing their excess weight before adolescence normalised girls’ cardiovascular risk profile but only partly reduced boys’ risk to normal.

Authors of the study, published today on bmj.com, also found that childhood BMI was as good an indicator of risk as waist measurement and fat mass.

Researchers in Bristol analysed data from the Avon Longitudinal Study of Parents and Children on 5235 children who had been 9-12 years old at the start of the study. Their BMI, waist circumference, and fat mass had been recorded at baseline. These children’s blood pressure and blood levels of cholesterol, glucose and insulin were measured when they reached 15-16 years old.

Children who had had a high BMI at 9-12 years old were much more likely than normal-weight children to have hypertension, and raised cholesterol and insulin levels, at 15-16 years old. For boys but not girls there was also an association of high BMI at 9-12 years with raised fasting blood glucose at 15-16. The association persisted even after adjustment for a wide range of socioeconomic and other factors including height, pubertal status and parents’ BMI. The authors were surprised to find that, contrary to earlier concerns, waist circumference and fat mass were no better than BMI at 9-12 years old for predicting heart disease risk at 15-16.

The study showed that weight loss was clearly beneficial: “Girls who were overweight/obese at age 9-12 but were normal weight by 15-16 had similar odds of adverse levels of risk factors to those who were normal weight at both ages.” But the picture was less straightforward for boys.

Boys who were overweight or obese aged 9-12 still had raised blood pressure, cholesterol and insulin at 15-16 even if they had returned to a normal weight by then, though their risks were not as high as for boys who had remained overweight/obese, or become so.
The authors say it is encouraging that children who lose excess weight can improve their cardiovascular risk profile, but they conclude: “Our findings highlight the need to shift the whole childhood population distribution of adiposity downwards and to develop interventions that safely and effectively reduce weight and improve cardiovascular risk factors in overweight/obese children.”

Cathy Ross, senior cardiac nurse at the British Heart Foundation, said: “It’s reassuring to see evidence that … overweight children who successfully tackle their weight problem by the time they reach adolescence appear to be able to reduce their risk of heart disease which is really positive news.

“However, we must work to prevent them becoming overweight in the first place as many obese children don’t achieve a healthy weight.

“Helping youngsters to understand lifestyle messages can be very challenging but making sure they balance healthy eating with regular physical activity is vital.”

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