William Haenszel

PASSIVE SMOKING AND LUNG CANCER

Evidence that environmental tobacco smoke may be a risk factor for lung cancer among individuals who themselves have never smoked tobacco products has been the subject of expert review over the last decade by several United States and international agencies. The most recent comprehensive review, published in 1993 by the United States Environmental Protection Agency, concluded that environmental tobacco smoke is a Group A (known human) carcinogen. This report, coming in the midst of rapid social and political change in attitudes towards public policy implications for protecting human health, has been the subject of considerable discussion. Issues involved in these discussions, as well as more recently published studies on the topic, are reviewed with respect to current thinking about the risk of lung cancer in passive smokers, particularly women, who are lifetime never-smokers.

Cancer of the colon and rectum and adenomatous polyps: A review of epidemiologic findings

The epidemiologic findings for intestinal cancer are reviewed and a model that may fit most of the facts is proposed for further testing. The major features of the model for colon cancer are: a. In low‐risk populations where the disease is “endemic,” colon cancers are concentrated in the cecum and ascending colon, female cases are preponderant, and most of the rise to the maximum incidence level has occurred by age 50–55; b. When a new etiologic factor is introduced into such a population, the transition from an “endemic” to an “epidemic” phase is first expressed as a rise in sigmoid cancers among older men over 55 years; c. A rise in female sigmoid cancers follows later, and the time lag is reinforced by a tendency for these female cases to appear at somewhat older ages than the male cases. Some tests of the model and implications for studies of suspect precursor lesions such as adenomatous polyps are indicated. In the latter connection, the need for comparative studies among populations subject to widely differing colon cancer risks is emphasized.

Dietary vitamins A and C and lung cancer risk in Louisiana.

The authors describe the results of a hospital‐based incident case‐control study of lung cancer conducted in a high‐risk region of southern Louisiana from January 1979 through April 1982. Dietary intake of carotene, retinol, and vitamin C was estimated from food frequency questionnaires administered to 1253 cases and 1274 controls. An inverse association was found between level of carotene intake and lung cancer risk, and this protective effect was specific for squamous and small cell carcinoma (odds ratio (OR) = 0.84, 95% confidence interval: 0.64–1.09, high intake). A stronger protective effect for these tumors was associated with dietary vitamin C intake (OR = 0.65, 0.50–0.87, high intake). A significant inverse gradient in risk with retinol intake was limited to adenocarcinoma (OR = 0.64, 0.44–0.94, high intake) and more pronounced among blacks.

Cancer mortality among foreign— and native-born Chinese in the United States

SMITH’S review of cancer mortality among Chinese in the United States as of 19491952 represented the first systematic compilation of the cancer experience in this racial group [I]. Prior to that time the occasional and fragmentary analyses of clinical and autopsy materials assembled in several countries lent support to the idea that the Chinese site profile of cancer risks differed on several counts from that observed for U.S. whites [l]. The 1959-1962 mortality tabulations for the continental United States and Hawaii included information on country of birth making possible the investigation of differences in risk between foreignand native-born Chinese. Since Smith’s publication, mortality and incidence data for selected Chinese populations in Asia have become available and the literature based on clinical and necropsy series has continued to grow. In reporting the more recent 1959-1962 data we have endeavored to place them in context with findings on Chinese populations elsewhere and to identify configurations of results that may suggest leads for further cancer studies of Chinese populations.

Risk factors of gastric precancerous lesions in a high‐risk Colombian population. I. salt

A case-control study for stomach cancer was conducted in a high-risk population in Nariño, Colombia to determine the risk of gastric precancerous lesions associated with salt intake measured by sodium-to-creatinine ratio of a single urine sample. Gastric biopsies and urine samples were collected from 263 individuals. Urinary sodium-to-creatinine ratios were studied in relation to histological data from the biopsies. Significantly high odds ratios for precancerous lesions (chronic atrophic gastritis, intestinal metaplasia, and dysplasia) were associated with higher sodium-to-creatinine ratios. Adjusted odds ratios (OR) of 2.50 for chronic atrophic gastritis and 7.24 for dysplasia were found. The association with intestinal metaplasia was weaker and not significant (OR = 1.57). Furthermore, an excess risk associated with adding salt to food at the table was found among patients with precancerous lesions (OR = 1.80). These findings support the two-step involvement of salt in the process of gastric precancerous lesions.

Epidemiology of cancer of the digestive tract

1. Epidemiology of Cancers of the Oral Cavity and Pharynx.- 2. Epidemiology of Esophageal Cancer: A Review.- 3. Epidemiology of Gastric Cancer.- 4. Epidemiology of Large Bowel Cancer.- 5. Epidemic Colon Cancer in Children and Adolescents?.- 6. Epidemiology of Gastrointestinal Lymphomas.- 7. Epidemiology of Primary Liver Cancer.- 8. Ethnogeographic Patterns in Gallbladder Cancer.- 9. Epidemiology of Cancer of the Gallbladder and Extra-Hepatic Biliary Passages.- 10. Epidemiology of Cancer of the Pancreas.

Epidemiology of Gastric Cancer

For many years the only known outstanding characteristics of gastric cancer epidemiology were its marked inter-population variation in frequency and its declining rates. Studies of migrants from high-risk countries to low-risk countries revealed that the high risk remained after migration, indicating that the experience of the first decades of life determines the outcome. This phenomenon has been explained on the basis of precursor lesions. Diet is suspected to play a major role in gastric cancer etiology but search for carcinogens in the diet has not led to convincing results. Epidemiologic and experimental studies have led to an etiologic hypothesis postulating intragastric synthesis of carcinogens, presently being tested. In this chapter we review the basic data contributing to our knowledge on the epidemiology of gastric cancer.

Risk factors of gastric precancerous lesions in a high‐risk Colombian population. II. nitrate and nitrite

Gastric nitrite content was studied in relation to precancerous lesions of the stomach in a case-control study conducted in a high-risk Colombian population. The proportion of detectable nitrite in gastric juice and the mean pH were significantly higher among those with precancerous lesions (chronic atrophic gastritis, intestinal metaplasia, and dysplasia) than among the controls (normal and superficial gastritis); the proportion and mean pH increased with the progression of histological changes from normal to dysplasia. Nitrite was not detectable in gastric juice with a pH less than 5.0. A positive association was found between the proportion of detectable nitrite and the risk of gastric precancerous lesions. Odds ratios of 4.39 for intestinal metaplasia and 24.72 for dysplasia remained significant after controlling for confounders. This finding suggests that nitrite may be a precursor of a mutagen that targets gastric epithelial cells.

Sodium intake and gastric cancer.

SummaryTo test the hypothesis that excessive intake of sodium chloride is a factor in gastric carcinogenesis, urinary excretion of sodium and creatinine was measured in Colombian subjects. Age, sex, weight, and height regression slopes for creatinine excretion were more similar in Colombia than in other countries. Sodium/creatinine (S/C) ratios correlated with 24-h urinary excretion of sodium revealed higher sodium excretion in populations with higher gastric cancer rates. The S/C ratios were not affected by circadial rhythms, making it possible to use single urine samples to investigate interpopulation differences in sodium excretion.

Epidemiology of Large Bowel Cancer

Prior to the 1960s, large-bowel cancer received little attention from epidemiologists. The turning point in the epidemiology of large-bowel cancer came with the systematic compilation of incidence data from cancer registries throughout the world. While these efforts were antedated by Segi’s compilations of cancer mortality statistics beginning with 1950, which described sizable gradients in large-bowel cancer death rates, the mortality data had been discounted on the grounds that the contrasts were inflated by intercountry differences in diagnostic and treatment facilities and death certification practices. This attitude began to change when the data in the first edition of ‘Cancer incidence in five continents’ (1) proved to be consistent with the mortality findings. Within a short time span, the concept of substantial intercountry variation in large-bowel cancer risk gained wide acceptance as a prime epidemiologic characteristic of this disease. This feature was stressed at the meeting of the International Working Party of the World Organization of Gastroenterology in 1963, which also noted differences in the presentation of tumors by anatomical segment in high- and low-risk populations (2). The international comparisons pointing to environmental factors as important risk determinants have been reinforced by observations that showed migrants coming to the United States from low-risk European countries and Japan to acquire within their lifetime the high risks characteristic of the host population of US whites (3, 4).