Morbidity, including fatal morbidity, throughout life in men entering adult life as obese

Abstract

Background: The association between obesity in adults and excess morbidity and mortality is well established, but the health impact throughout adult life of being obese in early adulthood needs elucidation. We investigated somatic morbidity, including fatal morbidity, throughout adulthood in men starting adult life as obese.

Methods: Among 362,200 Danish young men, examined for military service between 1943 and 1977, all obese (defined as BMI≥31.0 kg/m(2)), and, as controls, a random 1% sample of the others was identified. In the age range of 18-25 years, there were 1,862 obese, which encompass the men above the 99.5 percentile, and 3,476 controls. Information on morbidity was obtained via national registers. Cox regression models were used to estimate the relative morbidity assessed as first incidence of disease, occurrence of disease in the year preceding death and prevalent disease at time of death.

Results: From age 18 through 80 years the obese had an increased risk of becoming diseased by or die from a broad range of diseases. Generally, the incidence of first event, occurrence in the year prior to death, and prevalence at time of death showed the same pattern. As an example, the relative hazard of type 2 diabetes was constant throughout life at 4.9 (95% confidence intervals [CI]: 4.1-5.9), 5.2 (95% CI: 3.6-7.5), and 6.8 (95% CI: 4.6-10.1), respectively.

Conclusions: Our findings strongly support the continued need to avoid beginning adult life as obese, as obese young men experience an increased morbidity, including fatal morbidity, from many diseases throughout life.

Figure 1. Histogram of the Distribution of Body Mass Index at Draft Board Examination for the 5,238 Men.

Histograms illustrating the 100-fold enrichment of the right tail by the complete sampling of the obese cohort (BMI≥31.0).

Figure 2. Cumulative hazard plot for the obese versus the control cohort at corresponding ages from 18 through 80 years.

2a. First incidence of diabetes. 2b. Occurrence of diabetes in the year preceding death. 2c. Prevalent diabetes at time of death. To investigate whether the hazard ratio changed across age, we created graphs of the cumulative hazard from the obese group versus the controls at corresponding ages. For every age the cumulative hazard in the obese group is plotted against the cumulative hazard in the control cohort. The arrows denote corresponding ages in the two cohorts. The grey, broken line is the line of equality. The interpretation of the black line is that the excess risk, measured on the hazard ratio scale, in the obese group is constant across the age range of observation from 18 through 80 years of age, and thus the assumption of proportionality in the Cox model is fulfilled.