Socioeconomic position (again), causes and confounding.

237 white and black populations suggest that uncontrolled confounding is at play. Studies from populations of different faiths would be of interest, as would randomized trials of religious engagement. A systematic review of randomized trials of the effects of prayer is 'too inconclusive to guide those wishing to uphold or refute the effect of intercessory prayer on health care outcomes'. 7 Getting older, for this editor, is marked by more frequent visits to the dentist to ensure a full set of healthy teeth. The association between periodontal disease and mortality has been reported many times, and is very likely to be confounded, particularly by socioeconomic position and by smoking. In a large rural Chinese cohort study modest increased risks associated with tooth loss for all-cause mortality, upper GI cancers, heart disease, and stroke were found both in male smokers and non-smokers. 8 In women, who seldom smoked, the findings were less marked, particularly for heart disease. Confounding by socioeconomic position appeared unlikely as the participants came from very similar rural farming backgrounds. As with religious attendance, the interpretation of tooth loss, while reasonably easy to measure, is questioned by our commentators. 9 They suggest that people without teeth are probably less likely to suffer from periodontal disease and associated infections, the suspected cause of increased systemic diseases. If you really are losing the will to live, don't do it. Gunnell and colleagues have systematically reviewed the literature on the epidemiology and prevention of suicide by hanging. 10 Hanging in England and Wales, Australia, and New Zealand has become more popular over the last three decades, particularly in men. Of particular concern have been those who hang themselves in prisons and hospitals where there is a supposed duty of care by the institution. Fortunately such hangings make up only 10% of the overall proportion of cases, but as they are potentially much more preventable they are focused on in this report. The safer prison cell design presented by the authors would probably be viewed as an imaginable luxury by the British child workers who are the subject of our photoessay in this issue. 11 Finally, please register for the World Congress of Epidemiology 2005 which will be held in Bangkok from August 21 to 25, 2005. Following the terrible tsunami disaster, which has affected so many people in south and southeast Asia, this will be an opportunity to contribute to the …