beta-carotene and Respiratory-Tract-Infections

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

A high plasma carotenoid concentration could improve the immune response and result in decreased risk of infectious diseases. However, data on the relationship of plasma carotenoid concentration with acute respiratory infections, which occur frequently in elderly people, are scarce. We investigated, therefore, the relationship of plasma concentrations of six major carotenoids (beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene, lutein and zeaxanthin) with the incidence and severity of acute respiratory infections. Baseline data from an intervention trial were used. Participants were 652 non-institutionalized elderly people (> or =60 years old) enrolled via two community-based sampling strategies in the Wageningen area of The Netherlands in 1998-99. Plasma carotenoid concentrations were divided into quartiles, the lowest being the reference. Frequency and severity of episodes during the previous 1 year, i.e. staying in bed, medical consultation and episode-related medication, were self-reported by means of a questionnaire. On average 1.6 episodes per person were recorded. The incidence rate ratio of acute respiratory infections at high beta-carotene status was 0.71 (95 % CI 0.54-0.92) as compared with the low beta-carotene concentration group. No association was observed between beta-carotene and illness severity. alpha-Carotene, beta-cryptoxanthin, lycopene, lutein and zeaxanthin were not related to incidence or severity of the infections. We conclude that elderly people with a high plasma beta-carotene concentration may have a lower occurrence of acute respiratory infections.

Topics: Acute Disease; Aged; beta Carotene; Carotenoids; Cryptoxanthins; Dietary Supplements; Double-Blind Method; Female; Humans; Incidence; Lutein; Lycopene; Male; Regression Analysis; Respiratory Tract Infections; Severity of Illness Index; Xanthophylls; Zeaxanthins

Deficiency of serum vitamin A is one of the widespread public health problem among pre-school children in developing countries. A limited number of studies have been done about this problem in Turkey and there is no similar work done in Malatya. Serum vitamin A and beta-carotene levels in 56 pre-school age children who had recurrent acute respiratory infections (ARI) or recurrent diarrhoea were determined by a UV/VIS spectrometer. The results obtained were compared with 35 healthy pre-school age children. Serum vitamin A (51.66 +/- 8.10 micrograms/dL) and beta-carotene (82.88 +/- 18.5 micrograms/dL) levels in children with ARI's were found significantly lower than the control group (58.14 +/- 9.07 micrograms/dL and 131.43 +/- 22.38 micrograms/dL, respectively) (P < 0.001). Serum vitamin A (47.21 +/- 8.27 micrograms/dL) and beta-carotene (81.63 +/- 15.41 micrograms/dL) levels in children with recurrent diarrhoea were also found significantly lower than the control group (58.14 +/- 9.07 micrograms/dL and 131.43 +/- 22.38 micrograms/dL, respectively) (P < 0.001).

Topics: Acute Disease; beta Carotene; Case-Control Studies; Child; Child, Preschool; Deficiency Diseases; Developing Countries; Diarrhea; Female; Humans; Incidence; Infant; Male; Recurrence; Respiratory Tract Infections; Turkey; Urban Population; Vitamin A; Vitamin A Deficiency