Temporary reduction in BMI provides cardiovascular benefit

Even temporary changes to body mass index (BMI) over time affect risks for cardiovascular disease (CVD), according to an epidemiological study published May 21 in Lancet Diabetes and Endocrinology.

The study drew on a cohort from England, Scotland, and Wales whose health has been periodically tracked since birth in 1946. At the time of the study, the subjects were 60 to 64 years old. As this group has been followed over so long a period, researchers were able to obtain data from childhood, early adulthood, to present for a large cohort, enrolling a total of 1,273 out of 2,856 eligible participants.

“Unlike previous reports, in our study physical activity did not change the association between adiposity and cardiovascular phenotype,” wrote Marietta Charakida, MD, of University College London, and colleagues. “We noted an improvement in metabolic profile with lower concentrations of leptin and HbA and higher concentrations of adiponectin, in participants who dropped a BMI category during adulthood, even when this reduction was not sustained.”

BMI was used to define adiposity status, with BMIs of  less than 25 kg/m2 being considered normal, 25-29 kg/m2 overweight, and 30 kg/m2  or more obese. Hypertensive status was determined by means of a blood pressure of 140/90 mm Hg or greater at any time since age 36. Blood samples were taken. The participants were reviewed for carotid intima media thickness (cIMT), then assessed via questionnaires about lifestyle risk factors, including activity level, use of alcohol, drugs, or tobacco products and use of prescribed blood pressure medications.  

In the obese and overweight groups, increased systolic blood pressure (mean difference 2.13 mm Hg), leptin (mean difference 1.33 ng/mL), prevalence of diabetes (odds ratio 1.68) and lower adiponectin (mean reduction 1.46) per decade were reported.

They found that obesity from a young age affected overall cardiovascular health over the lifespan. However, if BMI status lowered by even one level, from obese to overweight or overweight  to normal, so did the overall risks for CVD, even if those changes weren’t permanent.

Childhood obesity seemed to have little effect in risks when the individual was a normal weight in adulthood, and saw similar risks to those who sustained a normal weight throughout their lifespan. However, individuals who were obese or overweight in early adulthood and remained through age 60 to 64 showed a cumulative effect on cIMT, much like those who had been obese from childhood onward.

John Deanfield, PhD, a member of the team from the University College London, said in a release, “Our study is unique because it followed individuals for such a long time, more than 60 years, and allowed us to assess the effect of modest, real-life changes in adiposity. Our findings suggest that losing weight at any age can result in long-term cardiovascular health benefits, and support public health strategies and lifestyle modifications that help individuals who are overweight or obese to lose weight at all ages.”

In an accompanying editorial, Elizabeth M. Cespedes, SM, and Frank B. Hu, MD, PhD, of the Harvard School of Public Health in Boston, commented that only 2 percent of study participants maintained a reduction in BMI category in adulthood. “Improvements in diet and increases in physical activity are crucial levers of long-term weight maintenance and prevention of weight gain in middle age and early adult hood,” they wrote. “Overweight individuals might have even greater health benefit from lifestyle changes such as increased physical activity than do normal weight individuals.”