The prevalence and etiology of nongenetic obesity and associated disorders.

The prevalence and etiology of nongenetic causes of obesity are reviewed, along with obesity-associated comorbidities of the metabolic syndrome. The role of nongenetic causes of obesity from environmental affluences, central nervous system developmental effects in adult obesity, and psychosocial disorders affecting obesity through central nervous system dysfunction are discussed. Obesity is now the major underlying cause of the metabolic syndrome and its alarmingly increased prevalence worldwide makes it the most preventable cause of chronic disease burden.