Estimating the risk of cardiovascular disease using an obese-years metric

Abstract

Objective: To examine the association between obese-years and the risk of cardiovascular disease (CVD).Study design: Prospective cohort study. Setting: Boston, USA. Participants: 5036 participants of the Framingham Heart Study were examined.Methods: Obese-years was calculated by multiplying for each participant the number of body mass index (BMI) units above 29 kg/m 2 by the number of years lived at that BMI during approximately 50 years of follow-up. The association between obese-years and CVD was analysed using time-dependent Cox regression adjusted for potential confounders and compared with other models using the Akaike information criterion (AIC). The lowest AIC indicated better fit.Primary outcome: CVD. Results: The median cumulative obese-years was 24 (range 2-556 obese-years). During 138 918 personyears of follow-up, 2753 (55%) participants were diagnosed with CVD. The incidence rates and adjusted HR (AHR) for CVD increased with an increase in the number of obese-years. AHR for the categories 1-24.9, 25-49.9, 50-74.9 and ≥75 obese-years were, respectively, 1.31 (95% CI 1.15 to 1.48), 1.37 (95% CI 1.14 to 1.65), 1.62 (95% CI 1.32 to 1.99) and 1.80 (95% CI 1.54 to 2.10) compared with those who were never obese (ie, had zero obese-years). The effect of obese-years was stronger in males than females. For every 10 unit increase in obese-years, the AHR of CVD increased by 6% (95% CI 4% to 8%) for males and 3% (95% CI 2% to 4%) for females. The AIC was lowest for the model containing obese-years compared with models containing either the level of BMI or the duration of obesity alone.Conclusions: This study demonstrates that obeseyears metric conceptually captures the cumulative damage of obesity on body systems, and is found to provide slightly more precise estimation of the risk of CVD than the level or duration of obesity alone.

Influence of obesity and physical workload on disability benefits among construction workers followed up for 37 years

“…Among the most common diagnoses for disability benefits in Sweden are MSD, CVD and mental disorders 10. We hypothesise that obese workers, and to a smaller extent overweight workers, have a higher risk of disability benefits—particularly through diseases related to the metabolic syndrome (primarily CVD and diabetes)11 and MSD such as osteoarthritis,12 sciatica,13 knee pain14 and low back pain 15…”

Prevalence and Trends in Lifetime Obesity in the U.S., 1988–2014

“…If the formerly-obese group is included in one omnibus “non-obese” category, as it is in much of the literature on obesity and health status, 44–50 it would understate the advantages of avoiding obesity altogether. Prior research has shown that failing to account for weight history may have substantially underestimated the effects of obesity on mortality.…”

Estimating the risk of type-2 diabetes using obese-years in a contemporary population of the Framingham Study

“…We argue that combining both the severity and the duration of obesity into a single construct of obese-years provided not only a better construct for estimating type-2 diabetes and cardiovascular disease ( 13 ), but also a better construct for estimating the risk of all-cause and cause-specific mortality compared to using the current constructs of BMI or obesity duration ( 24 ). It is recommended that the usefulness of the obese-years construct should be tested for estimating the health outcomes for other conditions, such as cancer, that have shown a limited association with the severity of obesity ( 25 ).…”

“…For the continuous variable of obese-years, HRs were presented per additional 10-unit increase of obese-years, where a one-unit increase in obese-years can represent an additional BMI level above ≥30 kg/m 2 or an additional year lived with obesity at a given BMI level. These categories were used to make the results of this study similar to the categories of previous findings ( 9 , 13 ), to facilitate comparison. Analyses were performed for total participants but also for categories stratified by gender and smoking status (current and never/ex-smokers,) as previous findings showed some variation in the relationship between obese-years and the risk of type-2 diabetes by gender and by smoking status ( 9 ).…”

“…Recently, two studies have reported that an obese-years construct is a better and more concise estimation the risk of type-2 diabetes ( 9 ) and cardiovascular disease ( 13 ), compared with a construct based on either the duration or severity of obesity alone. However, those studies have some limitations, as the population used relied on the relatively old prospective cohort of the original Framingham Heart Study (FHS) that began in 1948.…”