Lifestyle diseases

Lifestyle diseases (also called diseases of longevity or diseases of civilization) are diseases that appear to increase in frequency as countries become more industrialized and people live longer. They include Alzheimer's disease, atherosclerosis, cancer, chronic liver disease or cirrhosis, Chronic Obstructive Pulmonary Disease, Type 2 diabetes, heart disease, nephritis or chronic renal failure, osteoporosis, stroke, depression and obesity.

Causes
Factors in diet, lifestyle, and the environment are thought to influence susceptibility to the diseases listed above. Smoking, alcohol and drug abuse as well as the lack of exercise may increase the risk of certain diseases in later life.

International variation in cancer rates
A recent research paper published in the Lancet discussed the variation in cancer rates that evidences the existence of lifestyle diseases.

"In many Western countries, peoples' diet changed substantially in the second half of the twentieth century, generally with increases in consumption of meat, dairy products, vegetable oils, fruit juice, and alcoholic beverages, and decreases in consumption of starchy staple foods such as bread, potatoes, rice, and maize flour. Other aspects of lifestyle also changed, notably, large reductions in physical activity and large increases in the prevalence of obesity."

"It was noted in the 1970s that people in many Western countries had diets high in animal products, fat, and sugar, and high rates of cancers of the colorectum, breast, prostate, endometrium, and lung; by contrast, individuals in developing countries usually had diets that were based on one or two starchy staple foods, with low intakes of animal products, fat, and sugar, and low rates of these cancers."

"These observations suggest that the diets [or lifestyle] of different populations might partly determine their rates of cancer, and the basis for this hypothesis was strengthened by results of studies showing that people who migrate from one country to another generally acquire the cancer rates of the new host country, suggesting that environmental [or lifestyle factors] rather than genetic factors are the key determinants of the international variation in cancer rates."

Death statistics in the United States
In 1900, the top three causes of death in the United States were pneumonia/influenza, tuberculosis, and diarrhea/enteritis. Communicable diseases accounted for about 60 percent of all deaths. In 1900, heart disease and cancer were ranked number four and eight respectively. Since the 1940s, most deaths in the United States have resulted from heart disease, cancer, and other degenerative diseases. And, by the late 1990s, degenerative diseases accounted for more than 60 percent of all deaths.

In 1900, these top three causes of death were from communicable diseases. Since the 1940s, most deaths have come from a completely different category of disease called lifestyle diseases, which have been unmasked by the amelioration of diseases that previously caused death at younger ages.