Relationships in Canada between mortality from tumours of the gastrointestinal tract and marital status.

The mortality from tumours of the gastrointestinal tract in the Canadian population in 1970-72 was 16% higher in single than in married men (on the basis of age-adjusted rates), 25% higher in widowed men and 28% higher in divorced men. All these differences were unlikely to be due to chance. The rates were 4% higher for single women, 14% higher for widows and 22% higher for divorced women, compared with the married. The differences for single and divorced women were not significant. Substantial excess mortality was found in the unmarried for tumours of the mouth, pharynx and esophagus, and rectum; for tumours of the stomach and colon the excess was small or nonexistent. This variation between sites suggests that systematic errors in the census data used as denominators are not responsible for the high mortality for the unmarried from certain tumours. The effect is found in conditions for which treatment can have made little difference (e.g., a 75% excess mortality for tumours of the esophagus in single men compared with married) and in conditions for which differences in the use of medical facilities may have been important (e.g., a 44% excess mortality for tumours of the rectum in widowers).