The distribution of cholesterolemia and their relationship to total mortality, cardiovascular mortality, and cancer mortality were studied in a population of 125,513 men and 96,301 women, aged 16-90. Cholesterolemia in the population increases with age, up to age 50-60 for men and 60-70 for women. Beyond these ages, cholesterolemia decreases very significantly for men and moderately for women. Upon global examination of the entire population, the relationship between cholesterolemia and total mortality is observed as a U-shaped curve. The relationship with cancer mortality is slightly negative in men and appears as a U-shaped curve in women. The relationship with cardiovascular mortality in men is strongly positively correlated when adjusted for body mass index, blood pressure, tobacco consumption, gamma GT, and age. This relationship is not significant in women. There is a significant interaction in the relationship between cholesterolemia and mortality in men for weight, body mass index, vital capacity, maximum expiration volume per second, tobacco consumption, urea, serum albumin, hematocrit, hemoglobin, alkaline phosphatases, gamma GT, red cell volume, and sedimentation rate. Age is a fundamental variable to take into account. Thus, in men under 50 years of age at the time of inclusion, the relationship between cholesterolemia and total mortality shows a positive tendency, and the relationship with cardiovascular mortality is strongly positive. In men over 65 years of age, these relationships are negative. The same tendencies exist for cancer mortality. The reasons for these negative relationships may be related to the decreased cholesterol levels in subjects with malnutrition or diseases (essentially hepatic diseases); this is especially true in older subjects. These data push for additional in-depth analysis of these relationships and interactions, according to age categories and detailed causes of mortality. They also reinforce the idea that, in some patients, low cholesterolemia appears to be a marker for predisposition or the result, but not a cause, of cancer.