To examine the relation between small-airways abnormalities and specific lung functions, we performed pulmonary-function tests in 36 patients, of whom two were nonsmokers, one to three days before open-lung biopsy for localized pulmonary lesions. The primary lesion in the small airways was a progressive inflammatory reaction leading to fibrosis with connective-tissue deposition in the airway walls. Increase in disease in small airways correlated with deterioration in lung function. Lesions could be reliably detected (P less than 0.05) by tests for closing capacity, the volume at which air and helium flow ere equal (a test of airway caliber and elastic recoil), and the slope of phase III of the single-breath washout curve (which tests evenness of ventilation). These tests showed abnormalities at a time when the pathologic changes were still potentially reversible and when other tests were not appreciably changed.

Background: Obesity is becoming a serious public health issue and is related to lung dysfunction. Because both weight and height are indicators of body size, body mass index (BMI) may not be an ideal index of obesity in prediction of pulmonary dysfunction. Objective: The objective of the study was to determine the predictability of waist circumference (WC) and BMI for pulmonary function in adults with and without excess body weight. Design: A cross-sectional study of 1674 adults aged ͧ18 y was conducted in a rural community. Height, weight, WC, and pulmonary function were measured. Multivariate analysis was conducted. Results: WC was negatively associated with forced vital capacity and forced expiratory volume in 1 s, and the associations were consistent across sex, age, and BMI categories. On average, a 1-cm increase in WC was associated with a 13-mL reduction in forced vital capacity and an 11-mL reduction in forced expiratory volume in 1 s. The association between WC and pulmonary function was consistent in subjects with normal weight, overweight, and obesity. In subjects with normal weight, BMI was positively associated with forced vital capacity and forced expiratory volume in 1 s. Conclusion: WC, but not BMI, is negatively and consistently associated with pulmonary function in normal-weight, overweight, and obese subjects.Am J Clin Nutr 2007;85:35-9.

Background-Obesity increases the risk of cardiovascular disease, hypertension, diabetes, digestive diseases, and some cancers. Several studies have shown that excess weight or weight gain is related to pulmonary dysfunction, but this issue needs to be further clarified. Methods-The analysis was based on data of the Humboldt cohort study which was conducted in the town of Humboldt, Saskatchewan, Canada. The baseline survey in 1977 included 1202 adults, comprising 94% of all residents aged 25-59 years. Of these, 709 (59%) were followed up in 1983. Pulmonary function (forced vital capacity (FVC), forced expiratory volume in one second (FEVy) and maximal mid expiratory flow rate (MMFR)) and weight were measured in both surveys. Weight gain was determined by subtracting weight at baseline from weight at follow up. A residual analysis was used to examine the relationship between body mass index (BMI) at baseline, weight gain, and pulmonary function decline. Results-Both BMI at baseline and weight gain were significantly related to pulmonary function at follow up. The effect of weight gain during the study period, however, was more prominent. The results showed that both mean residual FVC and FEV, were highest in the group that gained <10 kg, lowest in the group that gained > 4.0 kg, and intermediate in the group that gained 1-03-9 kg in both men and women after taking age, BMI at baseline, and smoking into account. The effect of weight gain on pulmonary function was greater in men than in women. Multiple regression analysis showed that each kilogram of weight gain was associated with an excess loss of 26 ml in FVC and 23 ml in FEV, in men, and 14 ml and 9 ml respectively in women.Conclusions-Weight gain is significantly The relationship between obesity or excess weight and health and longevity has been receiving increasing attention.' 2 Numerous epidemiological studies have shown that obesity might increase the risk of cardiovascular disease, hypertension, diabetes, and cancer, as well as other diseases including arthritis, gout, kidney stones, and gallbladder disease.' A number of clinical studies3-"3 have described the effects of obesity on lung function test variables including functional residual capacity and expiratory reserve volume; however, the studies on the relationship between obesity and airways function have given inconsistent results.Body weight and weight gain as risk factors for pulmonary dysfunction have not been well documented by population based studies. In a cross sectional study of data from 3046 children and adults (seven years and over), Schoenberg et aP4 found that pulmonary function initially increased as weight increased and then decreased as weight continued to increase. They considered that the increase of pulmonary function with weight may reflect increasing muscle force, and the decrease with further weight gain may be due to obesity which limits the mobility of the thoracic cage. 14

We investigated the association of self-reported asthma and pesticide use in 1,939 male farmers. Regardless of age, smoking pack-years, and nasal allergic reactions, the prevalence of asthma was significantly associated with the use of carbamate insecticides (prevalence odds ratio = 1.8, 95% confidence interval: 1.1 to 3.1, p = 0.02). Self-reported asthmatics, in comparison with nonasthmatics, had significantly lower mean values for lung function test variables after adjusting for age and height and a higher prevalence of respiratory symptoms. These findings raise the possibility that exposure to agriculture chemicals could be related to lung dysfunction in exposed farmers.

Toxic gases, vapors, and particles are emitted from concentrated animal feeding operations (CAFOs) into the general environment. These include ammonia, hydrogen sulfide, carbon dioxide, malodorous vapors, and particles contaminated with a wide range of microorganisms. Little is known about the health risks of exposure to these agents for people living in the surrounding areas. Malodor is one of the predominant concerns, and there is evidence that psychophysiologic changes may occur as a result of exposure to malodorous compounds. There is a paucity of data regarding community adverse health effects related to low-level gas and particulate emissions. Most information comes from studies among workers in CAFO installations. Research over the last decades has shown that microbial exposures, especially endotoxin exposure, are related to deleterious respiratory health effects, of which cross-shift lung function decline and accelerated decline over time are the most pronounced effects. Studies in naïve subjects and workers have shown respiratory inflammatory responses related to the microbial load. This working group, which was part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating Hazards—Searching for Solutions, concluded that there is a great need to evaluate health effects from exposures to the toxic gases, vapors, and particles emitted into the general environment by CAFOs. Research should focus not only on nuisance and odors but also on potential health effects from microbial exposures, concentrating on susceptible subgroups, especially asthmatic children and the elderly, since these exposures have been shown to be related to respiratory health effects among workers in CAFOs.

The interaction between sex and smoking habits on pulmonary function was examined among 1,149 adults 25 to 59 yr of age in a rural community in Saskatchewan. Pulmonary function tests included FVC, FEV1, maximal midexpiratory flow rate (MMFR), the slope of phase III of the single-breath nitrogen test (delta N2/L), and closing volume as a percent of vital capacity (CV/VC). The data show that after fixing the effects of age, height, and weight by analysis of covariance, the adjusted means of delta N2/L in nonsmokers, ex-smokers, and current smokers were 0.92, 1.10, and 1.60% in women and 0.97, 1.05, and 1.23% in men, respectively. The difference in the adjusted means for delta N2/L between smokers and nonsmokers was larger in women than in men, 0.67% versus 0.26%, respectively. Multiple multivariate analyses show that the regression slopes for the residuals of FEV1, MMFR, and delta N2/L versus pack-years were significantly different between men and women. The regressions of FEV1 and MMFR decreased and the regression of delta N2/L increased with increasing pack-years more rapidly in women than in men. The combined effect of sex and pack-years on pulmonary function was not significant for ex-smokers. These data suggest that cigarette smoking may be more detrimental in its effects on lung function in women than in men.

No abstract

A B S T R A C T We measured the response to breathing a mixture of 80% helium and 20% oxygen (He) during a maximum expiratory flow-volume (MEFV) maneuver in 66 nonsmokers and 48 smokers, aged 17-67. All of the subjects studied had (forced expiratory volume in 1 s/forced vital capacity [FEV,.o/FVC]) X 100 of greater than 70%. While the flow rates of the smokers were within ±2 SD of those of the nonsmokers at 50% VC (Vmaxwo), both groups showed a reduction in flow with age (nonsmokers: r = -0.34, P < 0.01; smokers r = -0.52, P < 0.001). Nonsmokers showed no significant reduction with age in response to breathing He, while smokers showed a marked reduction with age (r = -0.63, P < 0.001 at Vmaxw). We also measured the lung volume at which maximum expiratory flow (Vmax) while the subject was breathing He became equal to Vmax while he was breathing air, and expressed it as a percent of the VC. This was the most sensitive method of separating smokers from nonsmokers. These results indicate that the use of He during an MEFV maneuver affords sufficient sensitivity to enable detection of functional abnormalities in smokers at a stage when Vmax while they are breathing air is normal.