Dr. Ron’s Research Review – January 8, 2014

© 2014

This week’s research review focuses on respiratory health.

Twenty years of clinical research, all points to the same thing: Loss of breathing power spells bad news for your strength, your heart, your health, and your brain! By the time you're 50, you've lost 40% of your breathing capacity!

In 1988, the European Society of Cardiology reported that even a moderate decline of lung volume increases your risk of heart disease by 200 percent. This is true even for those who have no family history of heart disease. (Cook and Shaper 1988)

In Denmark, the Copenhagen City Heart Study found that a loss of lung volume raises the risk of first-time stroke by over 30 percent boosts the risk of fatal stroke by 200 percent. (Truelsen, Prescott et al. 2001)

Data drawn from the Whitehall II study found lung function is a good 'summary' measure of overall functioning in early old age. (Singh-Manoux, Dugravot et al. 2011)

In general, for every 10% decrease in FEV1, all-cause mortality increases by 14%, cardiovascular mortality increases by 28%, and nonfatal coronary event increases by almost 20%. (Sin and Man 2005)

Dr. Ron


Articles

Breathlessness, lung function and the risk of heart attack

         (Cook and Shaper 1988) Download

Men with moderate or severe breathlessness had a greater than two-fold risk of suffering a major ischaemic heart disease (IHD) event compared to men with no evidence of breathlessness, based on 7.5-year follow-up in a prospective study of 7735 British men aged 40-59 years. Even after adjustment for other risk factors, including cigarette smoking, the relative risk remained two-fold. Men in the lowest fifth of the forced expiratory volume is 1 s (FEV1) distribution also had a two-fold risk of IHD compared to men in the highest fifth after similar adjustment. In part, the role of breathlessness as a risk factor for major IHD events was explained by its strong association with pre-existing, but usually undiagnosed, IHD. However, breathlessness was associated with an increased risk of heart attack even in men without any evidence of pre-existing IHD at screening. FEV1 was related to risk of a major IHD event in men without evidence of pre-existing IHD at screening and in men with previously undiagnosed IHD detected at screening. Measures of breathlessness and lung function could be more widely used in clinical situations and in screening as additional independent indicators of both unrecognized IHD and of risk for major IHD events.

Chronic obstructive pulmonary disease as a risk factor for cardiovascular morbidity and mortality

         (Sin and Man 2005) Download

Chronic obstructive pulmonary disease and other disorders, associated with reduced lung function, are strong risk factors for cardiovascular events, independent of smoking. Overall, when the lowest quintile of lung function, as measured by FEV1 is compared with the highest quintile, the risk of cardiovascular mortality increases by approximately 75% in both men and women. Having symptoms of chronic bronchitis alone increases the risk of coronary deaths by 50%. Reduced ratio of FEV1 to FVC by itself is a modest independent risk factor for coronary events, increasing the risk by 30%. However, if patients have ventricular arrhythmias, the risk of coronary events is increased twofold, suggesting that the cardiotoxic effects of obstructive airways disease are amplified in those who have underlying cardiac rhythm disturbances. In general, for every 10% decrease in FEV1, all-cause mortality increases by 14%, cardiovascular mortality increases by 28%, and nonfatal coronary event increases by almost 20%. These data indicate that chronic obstructive pulmonary disease is a powerful, independent risk factor for cardiovascular morbidity and mortality.

Association of lung function with physical, mental and cognitive function in early old age

            (Singh-Manoux, Dugravot et al. 2011) Download

Lung function predicts mortality; whether it is associated with functional status in the general population remains unclear. This study examined the association of lung function with multiple measures of functioning in early old age. Data are drawn from the Whitehall II study; data on lung function (forced expiratory volume in 1 s, height FEV(1)), walking speed (2.44 m), cognitive function (memory and reasoning) and self-reported physical and mental functioning (SF-36) were available on 4,443 individuals, aged 50-74 years. In models adjusted for age, 1 standard deviation (SD) higher height-adjusted FEV(1) was associated with greater walking speed (beta=0.16, 95% CI: 0.13, 0.19), memory (beta=0.09, 95% CI: 0.06, 0.12), reasoning (beta=0.16, 95% CI: 0.13, 0.19) and self-reported physical functioning (beta=0.13, 95% CI: 0.10, 0.16). Socio-demographic measures, health behaviours (smoking, alcohol, physical activity, fruit/vegetable consumption), body mass index (BMI) and chronic conditions explained two-thirds of the association with walking speed and self-assessed physical functioning and over 80% of the association with cognitive function. Our results suggest that lung function is a good 'summary' measure of overall functioning in early old age.

Lung function and risk of fatal and non-fatal stroke. The Copenhagen City Heart Study

         (Truelsen, Prescott et al. 2001) Download

BACKGROUND: Reduced lung function has been shown to be a significant predictor of non-fatal ischaemic heart disease, and of mortality due to cardiovascular disease. Fewer studies have analysed the relationship between lung function and risk of fatal or non-fatal stroke. The present study presents results on the relation between forced expiratory volume in one second (FEV1) and risk of incident and fatal first-ever stroke. SUBJECTS AND METHODS: The analyses are based on prospective cohort data from 12 878 eligible men and women aged 45-84 years, who participated in the first health examination of the Copenhagen City Heart Study in 1976-1978. The subjects were followed from day of entry until 31 December 1993. During that period 808 first-ever strokes occurred of which 153 were fatal within 28 days. Risk of incident and fatal stroke was estimated by means of Cox hazard regression. The analyses included adjustment for potential confounders: sex, age, smoking, inhalation, body mass index, systolic blood pressure, triglycerides, physical activity in leisure time, education, diabetes mellitus, and antihypertensive treatment. RESULTS: We found an inverse association between FEV1 and risk of first-time stroke. For each 10% decrease in FEV1 in percentage of expected, the relative risk (RR) increased 1.05 (95% CI : 1.00-1.09, P = 0.03). This represents an approximately 30% higher risk of stroke in the group of people with the lowest lung function as compared to the group with the highest lung function. The association between lung function and risk of fatal stroke resembled that of risk of incident stroke (fatal and non-fatal). The RR was 1.11 (95% CI : 1.03-1.19) for each 10% decrease in FEV1 in percentage of expected. This represents approximately a doubling of the risk between the highest and lowest lung function groups. CONCLUSIONS: This study shows that reduced lung function measured in percentage of predicted FEV1 is a predictor of first-time stroke and fatal stroke independent of smoking and inhalation. The high risk of fatal first-ever stroke in the group of people with low lung function may be of significance in both the design and interpretation of clinical trials.


References

Cook, D. G. and A. G. Shaper (1988). "Breathlessness, lung function and the risk of heart attack." Eur Heart J 9(11): 1215-22. [PMID: 3234413]

Sin, D. D. and S. F. Man (2005). "Chronic obstructive pulmonary disease as a risk factor for cardiovascular morbidity and mortality." Proc Am Thorac Soc 2(1): 8-11. [PMID: 16113462]

Singh-Manoux, A., A. Dugravot, et al. (2011). "Association of lung function with physical, mental and cognitive function in early old age." Age (Dordr) 33(3): 385-92. [PMID: 20878489]

Truelsen, T., E. Prescott, et al. (2001). "Lung function and risk of fatal and non-fatal stroke. The Copenhagen City Heart Study." Int J Epidemiol 30(1): 145-51. [PMID: 11171876]