Obesity risk factors become more ‘potent’ with increasing adiposity
MedWire News: Study findings suggest that some risk factors for obesity are weight dependent, which, the researchers say, may partly explain recent increases in obesity in Western society.
"Obesity is the second leading cause of preventable death," writes Paul Williams (Lawrence Berkeley National Laboratory, California, USA) in the journal PLoS ONE. "Even within the healthy weight range, greater weight is associated with significantly increased risk for hypertension, high cholesterol, and diabetes."
The findings show that the effects of parental adiposity, lower education, and diets characterized by high meat and low fruit content on obesity become progressively stronger with increasing body mass index (BMI).
Williams says: "This information may be helpful in advocating weight control in the young and lean who are likely unaware of the insidious nature of weight gain."
Using data from the National Walkers' and Runners' Health Studies, he assessed the relationship between population percentiles of BMI and obesity risk factors in over 14,000 men and 25,000 women whose physical activities fell short of nationally recommended levels.
After adjustment for age, race, and residual effects of physical activity, regression analysis revealed that the effect of education, diet, and family history on BMI became progressively stronger from the lowest to the highest BMI percentiles.
Specifically, the effect of education, diet, and family history on obesity was as much as 8.6-, 4.8-, and 2.6-fold greater for women in the 90th BMI percentile compared with those in the 10th percentile, respectively. For men, the respective effects were as much as 2.4-, 2.7-, and 1.7-fold greater for those in the 90th compared with the 10th BMI percentile.
These trends were statistically significant for both genders, notes Williams.
"The results are entirely consistent with our hypothesis that the risks for weight gain due to low socioeconomic status, diet, inheritance, and physical inactivity are minor in relatively lean individuals, and become progressively greater with increasing BMI," he says.
"The compounding effect of the risk factors with ever-increasing obesity will accelerate weight gain, which may explain, in part, the epidemic rise of obesity in the United States and elsewhere."
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By Nikki Withers