Abstract
Plasma total cholesterol levels totalling 16 758 from a workforce population of approximately 4000 were available for each of the years 1984 to 1988. These data were examined in conjunction with locally acquired solar radiation measurements for each month of the study period. There was an inverse relationship between solar radiation and cholesterol levels (r= −0.476, p=0.0007) for the four-year period. However, solar radiation can vary widely from year to year. In 1984, a good year for sunshine, the correlation was consequently stronger (r= −0.867, p=0.0003). This suggests that solar radiation accounted for 75% of the observed cholesterol variability for that year. Subsequent years experienced less solar radiation but, with the exception of 1986, demonstrated significant inverse correlations, being r= −0.648, p=0.022 and r= −0.579, p=0.0466 for 1985 and 1987 respectively. Since there can be marked regional differences in sunshine with our maritime climate, these findings may explain the geographical distribution of coronary heart disease (CHD) in the United Kingdom (UK). The high mean annual cloud cover, with relatively poor available solar radiation levels, may aso reveal why the UK has such a high population mean cholesterol level and incidence of CHD.