Obesity in adults has been shown to be associated with a significant reduction in life expectancy for both genders. The Framingham Study found that, at the age of 40 years, the lifespan of individuals with a BMI ≥ 30 kg/m2 was on average 6-7 years shorter than normal individuals with a BMI ≤ 24.9 kg/m2.
Several disease entities occur more frequently in the obese patients and many are clinically unsuspected or undiagnosed. Please refer to co-morbidities (diseases) associated with obesity.
The relationship between being overweight and obese on the development of new cardiovascular disease (CVD) risk factors and vascular disease end points (angina, MI, and CAD) has been studied. The patient population included Framingham Heart Study participants between the ages of 35 and 75 years, followed up for 44 years. The age-adjusted relative risk (RR) for CVD in obese men and women was 1.46 and 1.64, respectively. Interestingly, the study found that although excess adiposity was associated with a significantly increased RR for cardiovascular events (angina, CAD) in both sexes, only women showed a significantly increased age-adjusted RR for MI and death from CVD (1.68 and 1.67, resp.).
Multiple studies found that certain forms of cancer occur with a greater frequency in the obese population. Rapp et al. followed 67,447 men and 78,484 women for approximately 10 years and documented the incidence of cancer in the different BMI categories. In men, there was a significant increase in the incidence of colonic and pancreatic cancer with increasing BMI. In women, the study found a weak positive association between increasing BMI and cancer incidence in general. Women were also significantly more likely to develop non-Hodgkin’s lymphomas and uterine cancers.
Calle et al. followed more than 900,000 adults in the United States for 16 years and found that obese men and women were more likely to die from cancer than subjects of normal weight. The cancers that occurred with a higher frequency in the obese population included cancers of the esophagus, liver, colorectum, pancreas, gallbladder, kidney, non-Hodgkin lymphoma, and multiple myeloma. Obese men were more likely to die from prostatic and gastric carcinomas and obese women were more likely to die from ovarian, uterine, cervical, and breast carcinomas.
Obese individuals appeared to have a higher incidence of nosocomial postsurgical infections, aspiration pneumonia, community acquired pneumonia, and skin infections. Also, they are more likely to die from liver disease and complications of cirrhosis. Patients with nonalcoholic fatty liver disease (NAFLD) are more likely to experience disease progression in the setting of BMI ≥ 28 kg/m2, diabetes mellitus, and higher visceral adiposity index.