Epidemiologic reviews
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In preparing to undertake a clinical trial, it may be helpful to keep in mind Fredrickson's description of clinical trials (31): "Field trials are indispensable. They will continue to be an ordeal. ⋯ I have no doubt that when the problem is well chosen, the study is appropriately designed, and that when all the populations concerned are made aware of the route and the goal, the reward can be commensurate with the effort. If, in major medical dilemmas, the alternative is to pay the costs of perpetual uncertainty, have we really any choice?"
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The results presented in this review suggest that the impact of nutrition on obstructive lung disease is most evident for antioxidant vitamins, particularly vitamin C and, to a lesser extent, vitamin E. By decreasing oxidant insults to the lung, antioxidants could modulate the development of chronic lung diseases and lung function decrement. Antioxidant vitamins could also play an important role in gene-environment interactions in complex lung diseases such as childhood asthma. ⋯ This will allow researchers to evaluate the exposure-disease relation over an adequate time frame and obtain insight into the causality of the relation. Some of these studies should enroll infants and young children to determine the impact of early diet on respiratory health. Research should also focus on the equally challenging policy issues--namely, finding effective methods of convincing people to increase their daily consumption of fresh fruits and vegetables, to stop smoking cigarettes, and to minimize their environmental and occupational exposure to pollutants and other agents that cause respiratory disease.