Maintain young adult weight to help deter cardiovascular risk.
This observation from the National Heart, Lung, and Blood Institute-sponsored Coronary Artery Risk Development in Young Adults (CARDIA) study carries a hopeful message that has important implications. It suggests that greater public health emphasis should be placed on achieving weight stabilization in young and middle-aged adults. That's a more realistic goal than long-term maintenance of weight loss, according to Dr. Lloyd-Jones of North-western University, Chicago.
CARDIA is an ongoing multicenter epidemiologic study of African American and white men and women who were 18-30 years old at enrollment in 1985-1986. Dr. Lloyd-Jones' analysis was restricted to the 2,476 participants who underwent all six examinations conducted during the first 15 years of follow-up.
Subjects whose body mass index (BMI) increased by more than 2 kg/[m.sup.2] from baseline through year 15--that's about a 15-lb weight gain in most people--displayed a steady deterioration in all the cardiovascular risk factors measured in the examinations, namely triglycerides, HDL cholesterol, fasting blood glucose and insulin, and blood pressure. In contrast, participants whose BMI remained steady or rose by no more than 2 kg/[m.sup.2], or who actually lost weight and kept it off, had essentially no change in their risk factors.
For example, serum triglycerides in men who maintained a stable BMI rose 1.01 mg/dL annually, compared with 4.31 mg/dL annually in men whose BMI increased by more than 2 kg/[m.sup.2], he noted.
"That sounds like small change, but if you take that out for 15 years, it means that men who were initially lean but gained weight over the next 15 years increased their triglycerides by 65 points, compared with the other men whose triglycerides increased by only 15 points.
Similarly, systolic blood pressure in women whose weight remained stable rose an average of 0.13 mm Hg annually, compared with 0.64 mm Hg per year in women whose BMI rose significantly.
Among participants who gained weight, the rate of deterioration in cardiovascular risk factors was largely independent of their baseline BMI. In other words. CARDIA participants who were lean as young adults--say, with a baseline BMI of 22.5 kg/[m.sup.2]--but who ended up 15 years later with a BMI of 25 kg/[m.sup.2] experienced roughly the same increase in fasting blood glucose, triglycerides, and the other risk factors as subjects who started with a BMI of 30 kg/[m.sup.2] and ended up at 34 kg/[m.sup.2].
The incidence of metabolic syndrome during the follow-up period was 17% among subjects with significant weight gain, compared with just 2.2% in those whose BMI remained stable.
An ancillary findings of CARDIA was that even though conventional wisdom says that blood pressure increases with age, this didn't hold true in study participants who maintained stable body weight.
The bad news--no surprise here--is most people find it difficult to avoid significant weight gain as they move from young adulthood toward middle age. Indeed, fully 82% of CARDIA participants increased their BMI by more than 2 kg/[m.sup.2] over the course of 15 years.
"That's tragic in some ways. What I think most Americans need to focus on is cutting portion size. If we could just throw a third of the plate away, that would be a good start. The other thing is getting up off the couch and at least walking 20-30 minutes, three times per week as a bare minimum," he said.
BY BRUCE JANCIN
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|Title Annotation:||Clinical Rounds|
|Publication:||OB GYN News|
|Date:||Mar 1, 2005|
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