Pulmonary dysfunction and sleep apnea in morbid obesity.

The interplay between obesity and respiratory function has implications on lung functions, sleep disordered breathing and asthma. Severe obesity can restrict lung functions in childhood, but the extent of obstructive disease due to obesity in childhood is not clear. Obesity is clearly linked to the increased incidence of sleep disordered breathing in childhood. Most obese children with sleep disordered breathing have tonsillo-adenoidal hypertrophy contributing to sleep apnea. The presence of sleep apnea is a consideration in recommending bariatric surgery in the appropriate setting. Obese children with asthma tend to have more symptoms of asthma. Obese children, particularly girls, have a greater likelihood of developing asthma later in life. Further investigations of the various interactions between obesity and respiratory function are currently needed. Obesity is on the rise in US, reflected in the 3 times higher prevalence of overweight (body mass index > 95th percentile) in children 6 to 19 years of age (1). The prevalence of morbid or severe obesity, defined as a body mass index (BMI) of 40 or more in adults (2), has also increased from 2.9%, in the years 1988-1994, to 4.7% in the years 1999-2000 (3). In children, severe obesity has been defined as a BMI standard deviation score > 2.5 (4). The interactions between morbid obesity and the respiratory system have become more relevant today and can be broadly discussed in relation to lung functions and exercise capacity; sleep disordered breathing; and asthma.