Chronic obstructive pulmonary disease lowers work force participation rate
Chronic obstructive pulmonary disease (COPD) is associated with a 3.9 percent reduction in the work force participation rate, with moderate to severe COPD leading to significant unemployment in the United States. Canadian researchers studied 1,073 participants who had COPD out of 12,346 individuals who were part of the Third National Health and Nutrition Examination Survey (NHAMES III). (COPD involves persistent obstruction of the airways caused by either emphysema or chronic bronchitis.) In the United States and the industrialized world, these illnesses are caused by smoking. Approximately 17 million people in the U.S. are affected. According to a 1995 survey, approximately 70 percent of COPD patients were under the age of 65 and consumed 67 percent of total COPD office visits and 43 percent of hospitalizations. The study found that those with the most severe airflow restriction had a 14.4 percent reduction in work force participation, and those with the least disease had a 3.4 percent reduced rate. Based on NHAMES III data, approximately 9.4 million persons of working age in the U.S. had COPD in 1994. The authors estimated that excess unemployment due to COPD was approximately 366,600 persons in 1994, and that total lost productivity due to the disease cost $9.9 billion in that year. The study was published in the first issue for March of the American Thoracic Society’s peer-reviewed American Journal of Respiratory and Critical Care Medicine.
Sleep-disordered breathing in mildly obese men associated with glucose intolerance and insulin resistance
Researchers studying a community sample of 135 healthy but mildly obese men found that moderate to severe sleep-disordered breathing (SDB), as measured by a sleep test, was associated with glucose intolerance and insulin resistance. In the study group, SDB was “relatively common” with a 40 to 60 percent prevalence rate for abnormal breathing events during sleep. However, a more stringent SDB definition involving associated objective daytime sleepiness reduced the rate to 20 to 30 percent of the sample. (In insulin resistance, the body produces antibodies to insulin which interfere with its activity. In glucose intolerance, a glucose tolerance test assesses the ability of the body to metabolize its principal blood sugar.) Although the researchers did not find a relationship between fasting glucose and insulin levels and the severity of SDB, they saw a significant association between the apnea-hypopnea index (AHI), which measures disordered breathing, and 2-hour glucose and insulin levels. Among the study group, polysomnography revealed an average AHI of 17.4 events (at least 10-second pauses in breathing) per hour. According to the authors, an AHI of over 5 events per hour was associated with worsening glucose tolerance, after adjusting for body mass index and percent of bodily fat. The research appears in the first issue for March of the American Thoracic Society’s peer-reviewed American Journal of Respiratory and Critical Care Medicine.
Serum cortisol associated with lung function values in children
Higher serum values of the hormone cortisol in children are associated with better lung function values, especially at night, according to data from a study of 28 youngsters with stable asthma who were compared with 18 age-matched controls. Dutch investigators found that children with asthma had lower cortisol levels than did the healthy children, with midnight tests showing a significant difference. Cortisol, sometimes called hydrocortisone, is an organic compound of the steroid family. It is the principal hormone secreted by the adrenal glands, and is a potent anti- inflammatory agent. Cortisol demonstrates a circadian rhythm with its peak in the body at 8 a.m. and its lowest level around midnight. Although the pathogenesis of nocturnal airway obstruction is still unclear, the authors believe one potential cause could be decreased cortisol levels which, at night, precede the nocturnal fall in lung function values and may lead to less suppression of airway inflammation in susceptible persons, with subsequent airflow limitation. The investigators found that children with asthma had lower serum cortisol levels at all six daily time points measured in the study, compared with the healthy control group, and that this difference was statistically significant at midnight. The study is published in the first issue for March of the American Thoracic Society’s peer-reviewed American Journal of Respiratory and Critical Care Medicine.
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Journal
American Journal of Respiratory and Critical Care Medicine