Epidemiology of Obesity and Diabetes and Their Cardiovascular Complications

Abstract

Obesity and diabetes mellitus have reached epidemic proportions in the past few years. During 2011 to 2012, more than one-third of the US population was obese. Although recent trend data indicate that the epidemic has leveled off, prevalence of abdominal obesity continues to rise, especially among adults. As seen for obesity, the past few decades have seen a doubling of the diabetes mellitus incidence with an increasing number of type 2 diabetes mellitus cases being diagnosed in children. Significant racial and ethnic disparities exist in the prevalence and trends of obesity and diabetes mellitus. In general, in both adults and children, non-Hispanic blacks and Mexican Americans seem to be at a high risk than their non-Hispanic white counterparts. Secular changes in agricultural policies, diet, food environment, physical activity, and sleep have all contributed to the upward trends in the diabesity epidemic. Despite marginal improvements in physical activity and the US diet, the food environment has changed drastically to an obesogenic one with increased portion sizes and limited access to healthy food choices especially for disadvantaged populations. Interventions that improve the food environment are critical as both obesity and diabetes mellitus raise the risk of cardiovascular disease by ≈2-fold. Among those with type 2 diabetes mellitus, significant sex differences occur in the risk of cardiovascular disease such that diabetes mellitus completely eliminates or attenuates the advantages of being female. Given the substantial burden of obesity and diabetes mellitus, future research efforts should adopt a translational approach to find sustainable and holistic solutions in preventing these costly diseases.

Keywords: adolescents; adults; cardiovascular disease; diabetes mellitus; epidemiology; obesity; stroke.

Figure 1

Trends in age-adjusted prevalence of overweight and obesity categories in US adults aged 20–74 years, 1960–2012. Overweight is defined as a BMI≥25.0 kg/m² and <30.0 kg/m². Obese is defined as BMI ≥30.0 kg/m². Extremely obese is defined as BMI ≥40.0 kg/m². Data are derived from (1960–1962), NHANES I (1971–1974), NHANES II (1976–1980), NHANES III (1988–1994), and NHANES (1999–2012). Data sources: Ogden et al and Fryar et al.

Figure 2

Trends in overweight and obesity prevalence among children and adolescents, aged 2–19 years, by NHANES cycle. Overweight is defined as BMI ≥85^th percentile for age and sex and obesity defined as BMI ≥95^th percentile for age and sex. Class 2 obesity is defined as a BMI >120% of the 95^th percentile for age and sex or a BMI ≥35, whichever is lower. Class 3 obesity is defined as a BMI >140% of the 95^th percentile for age and sex or a BMI ≥40, whichever is lower. Data source: Skinner et al

Figure 3

Trends in age-adjusted prevalence of abdominal obesity (defined as waist circumference >88 cm in women and >102 cm in men) among adults by sex (panel A) and race (panel B), NHANES 1999–2012. Data source: Ford ES et al 2014

Figure 4

Trends in the prevalence of abdominal obesity among US children and adolescents aged 2–18 y by race, NHANES 2003–2004 to 2011–2012. Abdominal obesity is defined as waist circumference ≥ gender- and age-specific 90^th percentile based on NHANES III (1988–1994) data (Panel A) in all 2–18 year olds or a waist to hip ratio ≥0.5 among youth aged 6 to 18 years (Panel B). Data Source: Xi B et al 2014

Figure 5

Trends in age-adjusted rates of diagnosed diabetes per 100 civilian, non-institutionalized population in the US, by Race, 1980–2014. Data source: Centers for Disease Control and Prevention, National Center for Health Statistics, Division of Health Interview Statistics, data from the National Health Interview Survey