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Biomedical subjects

R Scragg

Publications and source records attributed to R Scragg.

95 records · Page 6Linked to original sources

Effect of influenza epidemics on Australian mortality.

The effect of influenza epidemics on all major causes of death has been examined. The results showed an increase in total mortality, and a fall in life expectancy, during epidemic years. Using the 1974 epidemic as an example, an increase in mortality was found in all age groups, with the greatest percentage in increases occurring in the very young and the very old. For all ages combined, the greatest percentage increases in mortality were for respiratory diseases, while the greatest absolute increases in mortality were for cardiovascular diseases, especially ischaemic heart disease. A thrombotic mechanism is suggested to explain the increase in mortality from cardiovascular diseases.

Adolescent↗

Alcohol consumption and blood pressure.

The relationship between alcohol consumption and systolic and diastolic blood pressure was examined in a representative population sample of 1,429 men and women aged 35-64 years in Auckland, New Zealand during 1982. Univariate plots demonstrated a U-shaped relationship between alcohol consumption and systolic and diastolic blood pressures in men and in women aged 50 years and older, with light and moderate drinkers (less than 0-34 g alcohol/day) having lower blood pressure levels than either nondrinkers or heavy drinkers. No clear relationship was seen in younger women. The U-shaped relationship in men, particularly for systolic blood pressure, remained after controlling for potential confounders, whereas in women aged 50 years and older, there appeared to be a threshold level of approximately four drinks per day, below which drinkers had similar blood pressure levels to nondrinkers. In the multivariate analyses, it was calculated that among men, light and moderate drinkers had systolic levels 4.8 mmHg lower and diastolic levels 1.7 mmHg lower than nondrinkers and heavy drinkers, while among women aged 50-64 years, nondrinkers, light drinkers, or moderate drinkers had systolic levels 10.2 mmHg lower and diastolic levels 4.5 mmHg lower than heavy drinkers. These findings suggest that in men and in women aged 50 years and older, there is a nonlinear relationship between blood pressure and alcohol consumption, and that there is a level of alcohol consumption, of approximately four drinks per day, below which drinkers have either similar or lower blood pressure levels compared to nondrinkers.

Adult↗

Seasonality of cardiovascular disease mortality and the possible protective effect of ultra-violet radiation.

Previous studies suggested that cardiovascular disease (CVD) seasonality is due to variations in temperature or respiratory disease prevalence. Another mechanism might be that the seasonal variation in ultra-violet (UV) radiation is responsible for the seasonality of CVD. An hypothesis is put forward that UV radiation, by increasing body levels of vitamin D, protects against CVD by decreasing the risk of thrombus formation. This hypothesis might explain the seasonal variations in CVD mortality and morbidity which decrease in summer, the higher CVD mortality in higher latitudes, and the inverse relationship between altitude and CVD mortality. It is speculated that this mechanism might involve a direct effect of vitamin D on the platelet, or might be mediated by a change in calcium metabolism.

Altitude↗