beta-carotene and Pneumonia

A previous analysis of the Alpha-Tocopherol Beta-Carotene (ATBC) Study on male smokers found that β-carotene supplementation increased the risk of pneumonia 4-fold in those who started smoking at the age of ≥21 years and smoked ≥21 cigarettes/d (a subgroup of 7 % of the study population). The present study hypothesised that β-carotene increases mortality in the same subgroup. The ATBC Study (1985-1993) recruited 29 133 Finnish male smokers (≥5 cigarettes/d) aged 50-69 years. Cox regression models were constructed to estimate the effect of β-carotene supplementation in subgroups. β-Carotene increased mortality (risk ratio 1·56; 95 % CI 1·06, 2·3) in those who started to smoke at ≥21 years and smoked ≥21 cigarettes/d. Within this subgroup, there was strong evidence of further heterogeneity. The effect of β-carotene supplementation was further modified by dietary vitamin C intake, fruit and vegetable intake (

Topics: Aged; alpha-Tocopherol; Antioxidants; Ascorbic Acid; beta Carotene; Cohort Studies; Diet; Dietary Supplements; Fruit; Humans; Male; Middle Aged; Nutrients; Odds Ratio; Oxidative Stress; Pneumonia; Smokers; Tobacco Smoking; Vegetables; Vitamin E; Young Adult

Vitamin E has influenced the immune system in laboratory studies. Dozens of animal experiments have found that vitamin E offered protection against infections caused by viruses and bacteria. Previously, significant heterogeneity was found in the effect of vitamin E supplementation on pneumonia in humans. The aim of this study was to examine how the effect of vitamin E on pneumonia risk depends on age.. Secondary analysis of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention study in Finland, 1985-1993, was performed. Participants were male smokers aged 50-69 years at the baseline who started to smoke at ≥21 years (N=7,469). Intervention was 50 mg/d of vitamin E for 5-8 years. The outcome was the incidence of hospital-treated, community-acquired pneumonia by the age at the follow-up.. Among 2,216 participants who smoked 5-19 cigarettes per day at baseline and exercised at leisure time, vitamin E supplementation reduced the incidence of pneumonia by 69% (95% confidence interval [CI]: 43%-83%; 57 pneumonia cases). In this subgroup, vitamin E prevented pneumonia in 12.9% of participants by the age of 74 years. Among 5,253 participants who smoked ≥20 cigarettes per day at baseline or did not exercise, the incidence of pneumonia was 14% lower in the vitamin E participants (95% CI: -38% to +21%; 139 cases). One-third of the participants quit smoking for a period, of whom 27 got pneumonia. The incidence of pneumonia was 72% (95% CI: 31%-89%) lower in the vitamin E group, and this benefit was also seen among those males who smoked ≥20 cigarettes per day at baseline or did not exercise.. Although the evidence of benefit from vitamin E against pneumonia in elderly males is strong in this analysis, the overall findings about vitamin E have been complex. Further research on vitamin E in nonsmoking elderly males is warranted.

Topics: Aged; alpha-Tocopherol; beta Carotene; Community-Acquired Infections; Dietary Supplements; Exercise; Finland; Follow-Up Studies; Humans; Incidence; Kaplan-Meier Estimate; Leisure Activities; Male; Middle Aged; Pneumonia; Risk Assessment; Risk Factors; Smoking; Vitamin E

Analyses in nutritional epidemiology usually assume a uniform effect of a nutrient. Previously, four subgroups of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of Finnish male smokers aged 50-69 years were identified in which vitamin E supplementation either significantly increased or decreased the risk of pneumonia. The purpose of this present study was to quantify the level of true heterogeneity in the effect of vitamin E on pneumonia incidence using the I 2 statistic. The I 2 value estimates the percentage of total variation across studies that is explained by true differences in the treatment effect rather than by chance, with a range from 0 to 100 %. The I 2 statistic for the effect of vitamin E supplementation on pneumonia risk for five subgroups of the ATBC population was 89 % (95 % CI 78, 95 %), indicating that essentially all heterogeneity was true variation in vitamin E effect instead of chance variation. The I 2 statistic for heterogeneity in vitamin E effects on pneumonia risk was 92 % (95 % CI 80, 97 %) for three other ATBC subgroups defined by smoking level and leisure-time exercise level. Vitamin E decreased pneumonia risk by 69 % among participants who had the least exposure to smoking and exercised during leisure time (7·6 % of the ATBC participants), and vitamin E increased pneumonia risk by 68 % among those who had the highest exposure to smoking and did not exercise (22 % of the ATBC participants). These findings refute there being a uniform effect of vitamin E supplementation on the risk of pneumonia.

Topics: Aged; alpha-Tocopherol; beta Carotene; Cohort Studies; Dietary Supplements; Effect Modifier, Epidemiologic; Exercise; Finland; Follow-Up Studies; Humans; Incidence; Male; Middle Aged; Pneumonia; Reproducibility of Results; Respiratory Tract Infections; Risk; Sedentary Behavior; Smoking; Statistics as Topic; Vitamin E

Vitamin E and beta-carotene affect various measures of immune function and accordingly might influence the predisposition of humans to infections. However, only few controlled trials have tested this hypothesis.. To examine whether vitamin E or beta-carotene supplementation affects the risk of pneumonia in a controlled trial.. The Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) study, a randomized, double-blind, placebo-controlled trial that examined the effects of vitamin E, 50 mg/d, and beta-carotene, 20 mg/d, on lung cancer using a 2 x 2 factorial design. The trial was conducted in the general community in southwestern Finland in 1985 to 1993; the intervention lasted for 6.1 years (median). The hypothesis being tested in the present study was formulated after the trial was closed.. ATBC study cohort of 29,133 men aged 50 to 69 years, who smoked at least five cigarettes per day, at baseline.. The first occurrence of hospital-treated pneumonia was retrieved from the national hospital discharge register (898 cases).. Vitamin E supplementation had no overall effect on the incidence of pneumonia (relative risk [RR], 1.00; 95% confidence interval [CI], 0.88 to 1.14) nor had beta-carotene supplementation (RR, 0.98; 95% CI, 0.85 to 1.11). Nevertheless, the age of smoking initiation was a highly significant modifying factor. Among subjects who had initiated smoking at a later age (> or =21 years; n = 7,469 with 196 pneumonia cases), vitamin E supplementation decreased the risk of pneumonia (RR, 0.65; 95% CI, 0.49 to 0.86), whereas beta-carotene supplementation increased the risk (RR, 1.42; 95% CI, 1.07 to 1.89).. Data from this large controlled trial suggest that vitamin E and beta-carotene supplementation have no overall effect on the risk of hospital-treated pneumonia in older male smokers, but our subgroup finding that vitamin E seemed to benefit subjects who initiated smoking at a later age warrants further investigation.

Topics: Aged; beta Carotene; Community-Acquired Infections; Confidence Intervals; Dietary Supplements; Dose-Response Relationship, Drug; Double-Blind Method; Drug Administration Schedule; Follow-Up Studies; Hospitalization; Humans; Lung Neoplasms; Male; Middle Aged; Pneumonia; Probability; Risk Assessment; Severity of Illness Index; Smoking; Treatment Outcome; Vitamin E

Beta-carotene has been suggested to be a factor for improving the immune system, which implies that it might decrease the risk of infections. We therefore analyzed whether beta-carotene supplementation influenced pneumonia risk in 14,564 Finnish male smokers of the Alpha-Tocopherol Beta-Carotene (ATBC) Study. There were 231 pneumonia cases in the beta-carotene group and 217 cases in the placebo group. Thus, beta-carotene had no effect on the average incidence of pneumonia, RR=1.07 (95% CI: 0.89-1.29). However, cigarette smoking exposure significantly modified the effect. Beta-carotene increased pneumonia risk by RR=4.0 (95% CI: 1.63-10) among 990 participants who started to smoke at the age of ≥21 y and smoked ≥21 cigarettes per day at the study baseline. However, beta-carotene had no influence on pneumonia risk for the remaining participants. We also analyzed the effect of beta-carotene on participants who quit smoking during the ATBC Study. Among 4,290 participants who quit smoking, the 58 pneumonia cases were evenly distributed between the beta-carotene and placebo groups with RR=0.93 (95% CI: 0.55-1.55). Accordingly, no evidence was found that beta-carotene decreased pneumonia risk; instead, it significantly increased the incidence of pneumonia in a subgroup that covered 7% of the study population.

Topics: Aged; alpha-Tocopherol; Antioxidants; beta Carotene; Case-Control Studies; Cigarette Smoking; Dietary Supplements; Finland; Humans; Male; Middle Aged; Pneumonia; Risk; Smoking

It has been proposed that moderate exercise may enhance the immune system. We evaluated whether physical activity at work or at leisure is associated with the risk of pneumonia, and whether the antioxidants vitamin E and beta-carotene affect pneumonia risk in physically active people. A cohort of 16 804 male smokers aged 50-69 years and working at study entry was drawn from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, which examined the effect of vitamin E, 50 mg/day, and beta-carotene, 20 mg/day, on lung and other cancers. Physical activity at work, and the type of leisure-time exercise, were recorded at study entry. We retrieved the first occurrence of hospital-treated pneumonia during a 3-year follow-up from the National Hospital Discharge Register (133 cases). Physical activity at work and at leisure had no association with the risk of pneumonia. In participants with physically loading jobs, neither vitamin E nor beta-carotene affected the risk of pneumonia. In participants carrying out moderate or heavy exercise at leisure, beta-carotene had no effect, but vitamin E reduced the risk of pneumonia by 50% (95% CI: 16-70%). Previously, exercise has been shown to affect diverse laboratory measures of the immune system which are, however, only surrogate markers for the resistance to infections. The lack of association between physical activity and the risk of pneumonia observed in our study emphasizes the problem of drawing conclusions from surrogate end points. The finding that vitamin E reduced the risk of pneumonia in persons carrying out leisure-time exercise warrants further study.

Topics: Aged; Antioxidants; beta Carotene; Cohort Studies; Dietary Supplements; Exercise; Finland; Follow-Up Studies; Humans; Leisure Activities; Male; Middle Aged; Motor Activity; Pneumonia; Randomized Controlled Trials as Topic; Registries; Risk Factors; Smoking; Vitamin E; Work

Topics: Animals; beta Carotene; Community-Acquired Infections; Dietary Supplements; Humans; Lung; Mice; Pneumonia; Pulmonary Edema; Rats; Vitamin E