Thinness and mortality

The relationship of thinness to mortality was examined in White adult members of the Kaiser Permanente Medical Care Program who had at least three multiphasic health checkups between 1964 and 1972, with mortality follow-up through 1980. A detailed comparison was performed of the mortality patterns of "thin" (decile 1 of Quetelet's index) and "average" weight (deciles 4 and 5) cohort members who were age 40-79 years and free of illness at the beginning of follow-up. Thin male (relative risk 1.6, 95 per cent confidence limits 1.0, 2.6) and female (R.R. 2.1, 95 per cent C.L. 1.1, 3.9) current cigarette smokers were at increased risk of mortality compared with average weight smokers. Unmeasured differences between thin and average weight smokers with respect to quantity of cigarettes smoked may have contributed to the apparent association of thinness with mortality in smokers. Thinness was not associated with increased mortality in never smokers and ex-smokers (R.R. 1.0 in men and women). As association of long-term weight loss with mortality was present in thin and average weight men and in thin women.

Smoking habits among multiphasic examinees, 1979 to 1984

In tabulating the smoking habits of 95,744 residents of the San Francisco Bay Area, as reported between July 1979 and June 1984 at multiphasic health checkups, the prevalence of current smoking was found to be higher in men than in women aged 30 years and above, but in those younger than 30 the reverse was true. In every age group, compared with male smokers, female smokers tended to smoke fewer cigarettes per day, to inhale less and to smoke cigarettes with lower tar and nicotine yield. Blacks showed the highest percentage of smokers, whites were second highest and Asians were lowest, with Asian women being substantially lower than other race-sex groups. On average, white smokers smoked more cigarettes per day and inhaled more than did black smokers, but whites were more apt to smoke low-yield cigarettes. Compared with a 1964 to 1968 study in the same setting, there has been a decrease in the prevalence of cigarette smokers but, among smokers, a higher proportion in 1979 to 1984 smoked at least 20 cigarettes per day. During the 1979 to 1984 period, there were small downward trends in the prevalence of cigarette smoking in men and white women and in the prevalence of heavy smoking among male smokers, but there was no apparent increase in the use of lower-yield cigarettes by smokers. Although this study group contained relatively fewer smokers, most of the age, sex and racial differences and long-term trends parallel what has been observed nationally.

Serum cholesterol and large bowel cancer. A case-control study

A case-control study of the relationship of serum cholesterol to large bowel cancer incidence was performed for 245 members of the Kaiser Permanente Medical Care Program in northern California. Five controls were obtained for each case, matched for age, sex, race, and time of examination. The mean serum cholesterol levels of cases were not significantly different from those of controls for all colorectal cancers, right-sided colon cancers, and left-sided colon cancers. Analysis by quartiles of serum cholesterol level suggested neither a direct nor an inverse relationship between serum cholesterol and large bowel cancer, and there was no evidence of a threshold value below which the risk of cancer increased. The study did not support the findings from other studies of an inverse relationship between serum cholesterol and large bowel cancer.

Cholesterol, cancer, and public health policy

A review of prospective cardiovascular epidemiologic studies reveals an inverse relationship between serum cholesterol levels and cancer mortality in half the studies in which this relationship has been examined. This inverse relationship has been demonstrated only for males, and is most consistently demonstrated for large bowel cancer. However, a review of international and intergroup epidemiologic data reveals that dietary fat intake is positively correlated with mortality rates for all cancers and for large bowel cancer. Internationally, there is also a positive correlation between mortality rates for ischemic heart disease and for cancer, as well as a positive correlation between mean population values of total serum cholesterol levels and cancer mortality. The biologic plausibility of the relationship between low serum cholesterol levels and cancer, and between high dietary fat intake and cancer are examined, with particular reference to large bowel cancer. Models are proposed to provide a coherent framework in which both low serum cholesterol levels and high dietary fat intake are risk factors for carcinogenesis. It is concluded that, on the basis of present knowledge, limitation of dietary fat and cholesterol intake is a prudent public health measure for the prevention of both coronary heart disease and cancer.