Height and risk of cancer

Editor—In two separate cohort studies Gunnell et al1 and Davey Smith et al2 found an association between height and non-smoking related cancers. An accompanying editorial indicates that causality for this association is supported by studies in animals.3 None of the articles, however, examines the possibility of bias from survival selection in the cohort studies. Cancer and heart disease are the main causes of death in old age but the mean age of death for heart disease is younger than for cancer. Heart disease is strongly associated with smoking and also with short stature. Is it possible that there is selective survival of taller people because shorter people die earlier from heart disease? This hypothesis is strengthened by the lack of association with smoking related cancers: smoking would be expected to cause heart disease first. A test of this hypothesis would be to compare at the same mean age the heights of people with heart disease with the heights of people who had died from cancer. Did the referee ask for this? The two papers would be strengthened if the issue could be addressed.