Adult mortality in Berlin, NH, from 1961 to 1967

Breathlessness, phlegm and mortality: 26 years of follow-up in healthy middle-aged Norwegian men

OBJECTIVES

It is well known that pulmonary function is associated with all-cause and cardiovascular (CV) death. Less is known about the association between respiratory symptoms and mortality and whether such an association is independent of physical fitness. In this study, we assessed the association of breathlessness and productive cough with CV and all-cause mortality over 26 years.

DESIGN

Prospective occupational cohort study.

SETTING AND SUBJECTS

In 1972-75, 1999 apparently healthy men aged 40-59 years were recruited to the study from five companies in Oslo, Norway. At study entry clinical, physiological and biochemical parameters including respiratory symptoms, spirometry, and an objective assessment of physical fitness were measured in all subjects, of whom 1,623 had acceptable spirometry. The data was analysed using Cox proportional hazards analysis, adjusting for age, lung function, physical fitness, and other possible confounders, with mortality until 2000.

RESULTS

After 26 years (range 25-27), 615 men (38%) had died, of whom 308 (50%) from CV deaths. In multivariable proportional hazards models, 'having phlegm winter mornings' [hazard ratio (HR) 1.30, P = 0.01], 'breathlessness when hurrying/walking uphill' (HR 1.43, P = 0.005) and combinations of the two symptoms remained significant predictors of all-cause mortality. None of six respiratory symptoms were significant predictors of CV mortality in multivariable models.

CONCLUSIONS

Phlegm, breathlessness and combinations of them were associated with all-cause mortality, even after adjusting for physical fitness, known CV and other risk factors such as smoking, and lung function. The finding of an association also after adjustment for physical fitness is new. In contrast, none of the six respiratory symptoms individually or in combination were associated with CV mortality in multivariable analysis.

Relation of ventilatory impairment and of chronic mucus hypersecretion to mortality from obstructive lung disease and from all causes

The relation of ventilatory impairment and chronic mucus hypersecretion to death from all causes and death from obstructive lung disease (chronic bronchitis, emphysema and asthma) was studied in 13,756 men and women randomly selected from the general population of the City of Copenhagen. During the 10 year follow up 2288 subjects died. In 164 subjects obstructive lung disease was considered to be an underlying or a contributory cause of death (obstructive lung disease related death); in 73 subjects it was considered to be the underlying cause of death (obstructive lung disease death). Forced expiratory volume in one second, expressed as a percentage of the predicted value (FEV1% pred), and the presence of chronic phlegm were used to characterise ventilatory function and chronic mucus hypersecretion respectively. For mortality analysis the proportional hazards regression model of Cox was used; it included age, sex, pack years, inhalation habit, body mass index, alcohol consumption, and the presence or absence of asthma, heart disease, and diabetes mellitus as confounding factors. By comparison with subjects with an FEV1 of 80% pred or more, subjects with an FEV1 below 40% pred had increased risk of dying from all causes (relative risk (RR) = 5.0 for women, 2.7 for men), a higher risk of obstructive lung disease related death (RR = 57 for women, 34 for men), and a higher risk of obstructive lung disease death (RR = 101 for women, 77 for men). Chronic mucus hypersecretion was associated with only a slightly higher risk of death from all causes (RR = 1.1 for women, 1.3 for men). The association between chronic mucus hypersecretion and obstructive lung disease death varied with the level of ventilatory function, being weak in subjects with normal ventilatory function (for an FEV1 of 80% pred the RR was 1.2), but more pronounced in subjects with reduced ventilatory function (for an FEV1 of 40% pred the RR was 4.2). A similar though statistically non-significant trend was observed with regard to obstructive lung disease related death. This study shows that impaired lung function is very strongly related to total mortality, obstructive lung disease related mortality, and obstructive lung disease mortality and suggests that chronic mucus hypersecretion, in those with impaired ventilatory function, is also a significant risk factor for death from obstructive lung disease.

Respiratory symptoms as predictors of 27 year mortality in a representative sample of British adults

OBJECTIVE

To examine associations between reported respiratory symptoms (as elicited by questionnaire) and subsequent mortality.

DESIGN

Prospective cohort study.

SETTING

92 General practices in Great Britain.

PARTICIPANTS

A nationally representative sample of 1532 British men and women aged between 40 and 64.

MAIN OUTCOME MEASURES

Mortality from all causes, cardiovascular disease, lung cancer, and chronic bronchitis.

RESULTS

Subjects were interviewed in 1958 regarding various respiratory symptoms (including cough, phlegm, breathlessness, and wheeze) by using a questionnaire which formed the basis of the Medical Research Council's questionnaire on respiratory symptoms. By the end of 1985, 889 deaths had been reported, including 51 in men due to chronic bronchitis. After adjustment for differences in age and smoking habits death rates from chronic bronchitis in men who reported symptoms were greater than those in men who did not for each of the symptoms examined. The adjusted mortality ratios were 3.4 (95% confidence interval 1.8 to 6.5) for morning cough, 3.7 (2.0 to 6.9) for morning phlegm, 6.4 (3.0 to 13.8) for breathlessness when walking on the level, and 10.5 (4.4 to 24.6) for wheeze most days or nights. Mortality ratios were also significantly raised for four episodic symptoms not usually included in more recent respiratory symptom questionnaires--namely, occasional wheeze (mortality ratio 6.0; 95% confidence interval, 2.4 to 15.1), weather affects chest (5.7; 3.1 to 10.3), breathing different in summer (4.9; 2.8 to 8.6), and cold usually goes to chest (3.7; 2.0 to 6.8). The excess mortality associated with these symptoms remained significant after further adjustment for breathlessness or phlegm. Ratios for all cause mortality in men and women were also significantly raised for most respiratory symptoms, death rates being some 20-50% higher in people reporting symptoms after adjustment for age, sex, and smoking. Breathlessness was the only symptom significantly associated with excess mortality from cardiovascular disease (mortality ratio 1.4 (95% confidence interval 1.0 to 1.9) for breathlessness when walking on the level). Ratios were generally around unity and not significant for mortality due to lung cancer.

CONCLUSIONS

The results suggest that episodic symptoms, which often do not appear in standard respiratory questionnaires, predict subsequent mortality from chronic obstructive airways disease. This supports the hypothesis that reversible airflow obstruction may be a precursor of progressive and irreversible decline in ventilatory function.

Changes in lung function determined longitudinally compared with decline assessed cross-sectionally. The Cracow Study

Longitudinal annual changes in lung function (FEV1) with cross-sectional estimates have been compared in the sample of Cracow inhabitants who underwent epidemiological follow-up on chronic nonspecific chest diseases. The annual rate of FEV1 decline was faster in men than in women. Among male smokers the FEV1 decline rate was 30% greater, while in women smokers 9% faster than in non-smokers. The cross-sectional estimates for annual changes differed in both surveys carried out in the interval of 13 years and were not very much consistent with the average longitudinal annual decline observed in the sample. However, the prediction of annual decline across the age groups showed large inconsistencies. They resulted from the curvilinear pattern in lung function decline over the age groups. It was found that the lung function in the elderly appeared to be more homogeneous and the acceleration of decline rates slowed down. There is some evidence that the flattening of the decline curve among elderly might have been influenced by the selection bias.

Mortality and morbidity in a pulp and a paper mill in the United States: a ten-year follow-up

Two hundred and seventy-one men seen in 1963, who worked in a pulp and a paper mill, were followed up ten years later, in 1973. Death certificates were obtained for those who died. There did not appear to be any increased mortality in the group, nor was there any increased specific cause of death. A morbidity study of 200 men seen at both times did not show any differences in respiratory symptoms or prevalence of chronic non-specific respiratory disease. Analysis of pulmonary function showed little, if any, difference between groups. Analysis of retired, deceased, and still-working categories did suggest that exposures to Cl2 or SO2 might have a slight adverse effect on pulmonary function.

A clinical and lung function study of chronic lung disease and asthma in coastal Papua New Guinea

A prevalence survey on the island of Karkar had previously shown that chronic lung disease was common in both sexes after the age of 35 years and that, in part, this was related to the smoking of home-grown air-cured tobacco. To investigate the nature of this chronic lung disease, 37 nontuberculous subjects with reduced ventilatory capacity (forced expiratory volume in one second less than 75% predicted) underwent clinical and lung function investigations. Ninety-two per cent had adventitiae, 62% had chronic productive cough and 54% had dyspnoea on exertion. Lung function tests showed an irreversible obstructive defect with a variable, but on average, only moderately reduced transfer factor. The chest radiography showed evidence of hyperinflation in 38% of cases but non had narrowing or loss of pulmonary vessels suggestive of emphysema. "Inflammatory changes" occurred in 35% and were associated with a mild but significant element of restriction. The results suggest that chronic bronchitis and chronic bronchiolitis were the main underlying abnormalities and that emphysema was comparatively unimportant. Asthma appeared to be relatively uncommon, especially in children. The clinical and lung function findings in 16 asthmatics were essentially similar to those observed in asthmatics elsewhere and the atopic status of asthmatics and controls was similar to that observed in developed societies. In common with Highland asthmatics however, the age at onset was in early adult life rather than in childhood.