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Study Objectives: The aim was to test whether cataract is associated with higher lifetime exposure to sunlight, and whether antioxidants protect against cataract., Design: This was a cross sectional survey of eye disease, with assessment of antioxidant status in a subgroup., Setting: Hong Kong fishing communities in 1989., Participants: 685 men and women aged 55 to 74 years old were included in the study, of whom 367 (54%) attended hospital for detailed examination., Measurements and Main Results: At a mobile clinic visual acuity and lens opacities were assessed, and using a questionnaire, occupational history and lifetime exposure to sunlight. At hospital ophthalmic measurements were repeated and blood was taken for measurement of plasma vitamin C, vitamin E, and total carotenoids, and red cell activities of glucose-6-phosphate dehydrogenase, glutathione peroxidase, superoxide dismutase, and catalase. Higher grades of cataract (particularly nuclear cataract) tended to be more common in subjects with the most sun exposure, although not to the point of statistical significance. In contrast to earlier studies, no association was found with antioxidant status., Conclusions: The findings give some support to the hypothesis that sunlight causes cataract. The absence of a relation to antioxidant status may be because blood levels of antioxidants at one point in time do not adequately reflect a subject's past metabolic state, and particularly the past activity of antioxidants in the lens.

The factors which determine whether an individual is a methane excretor or a nonexcretor are not clearly understood. Genetic makeup, ethnic origin, diet, environment, or an interaction of all these factors have been implicated. In order to delineate the incidence, the age of onset, and environmental factors that may influence the excretion of methane in our community, we investigated a total of 425 Chinese children in Hong Kong (204 females, 221 males). End-expiratory breath samples were collected after an overnight fast and measured by gas-chromatography using a flame ionization detector. Thirty one children (7.3%) excreted at least 1 ppm methane above the ambient level (median = 6.4, range = 1.8-26.0 ppm). There was no difference in methane excretion status and pattern between the sexes or between children who lived at home and those who lived at an institution. There was a general increase in the number of methane excretors with age, but a statistically significant increase was reached only after 14 years of age. The amount of methane excreted was unrelated to age and there were no excretors detected under the age of 5 years. It is concluded that the methane excretion pattern of these children was generally similar to those previously reported from other regions, but the incidence is much lower and the age of onset appears to be more gradual.

A double-blind placebo trial of vitamin C has been undertaken in 94 elderly "long-term" inpatients known to have initially low levels of plasma and leukocyte vitamin C (mean values 0.17 mg/100 ml plasma; 10.1 microgram/10(8) leukocytes). At the end of 2 months treatment, plasma and leukocyte vitamin C had increased considerably in those receiving C supplements, and in this group there were slight but significant increases in the mean values for body weight (0.41 kg), plasma albumin (0.46 g/l), and prealbumin (25.4 mg/l) compared with those receiving placebo therapy where there were decreases of 0.60 kg, 0.53 g/l, and 7.0 mg/l, respectively. There was also some clinical improvement as indicated by reductions in purpura and petechial hemorrhages in those receiving vitamin C, but no changes in mood or mobility were observed.