Weight Loss in Early Adulthood Slashes Mortality Risk in Obese Patients

August 18, 2020

An analysis of NHANES data suggests those who lost weight between early adulthood and midlife could have drastically reduced their risk of mortality.

New research from the University of Boston School of Public Health is shedding further light on the effects of weight loss in early adulthood and midlife on mortality risk.

Results of the study, which followed more than 20k patients for more than a decade, suggests obese patients who lost weight during early adulthood had a 54% lower risk of mortality compared to those who were still considered obese at the end of the study.

"The results indicate an important opportunity to improve population health through primary and secondary prevention of obesity, particularly at younger ages," said lead investigator Andrew Stokes, PhD, an assistant professor of global health at Boston University School of Public Health, in a statement.

With the prevalence and burden of obesity on public health continuing to grow, Stokes and a team of colleagues from Boston University to assess how weightless in early adulthood and midlife might impact the mortality risk in obese patients. To do so, they designed their study as a cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) III, which began between 1988-1994.

From NHANES, investigators identifier a s cohort of 24,205 patients for inclusion in their study. This cohort had a mean follow-up time of 10.7 years, a mean BMI of 29.0 at baseline, 49% of participants were women, and 11,567 were non-Hispanic White. In total, 5846 deaths occurred during the study period.

Patients included in the study were asked to recall weight at 25 years and weight 10 years before their age at baseline, which were defined as early adulthood and midlife, respectively. Weight loss patterns were examined from early adulthood to midlife. To describe weight change patterns, investigators created 3 broad categories defined as weight maintenance, weight gain, and weight loss.

Investigators pointed out NHANES included data related to confounders, such as age, sex, race/ethnicity, educational level, country of birth, smoking status, and survey year.

The mean BMI at age 25 was 23.7 (4.1) and this figure increased to to 27.2 (5.7) at midlife. At baseline, the mean BMI was 29.0 (6.1) at baseline. Upon analysis, 56.2% of patients maintained their original BMI categories. Overall weight loss was uncommon in the study cohort, with just 1.3% of overweight individuals in early adulthood decreasing their BMI to a normal weight by midlife. Additionally, 0.8% of patients went from the obese to overweight group and 0.2% went from obese to normal.

Upon analysis, losing weight and changing from the obese to overweight category was associated with a 54% (HR, 0.46; 95% CI, 0.27-0.77) reduction in mortality risk compared to those who were obese from early adulthood to midlife. According to results, 3.2% (95% CI, 1.6%-4.9%) of early deaths could have been avoided if those who maintained an obese BMI reduced weight to an overweight BMI by midlife. Investigators also determined 12.4% (95% CI, 8.1%-16.5%) of early deaths occurring in the study cohort may be attributable to having weight in excess of normal BMI range at any point during early adulthood and midlife.

"Although this study focused on preventing premature deaths, maintaining a healthy weight will also reduce the burden of many chronic diseases such as hypertension, diabetes, heart disease, and even cancer," said study co-author JoAnn Manson, MD, DrPH, chief of preventive medicine at Brigham and Women's Hospital, in the aforementioned statement.

This study, “Association of Weight Loss Between Early Adulthood and Midlife With All-Cause Mortality Risk in the US,” was published in JAMA Network Open.