In reply: The spirituality and health supplement was a compendium on religion and spirituality in clinical practice, based on recent presentations at the National Spirituality and Health Conference. The authors sought to highlight clinically relevant research exploring associations between religiosity and health.

Clarke and Jackson express concerns about the quality of the literature on intercessory prayer. Yet all the studies on intercessory prayer cited in our article on prayer and medicine1 belong to references included in the 2007 Cochrane database systematic review on the subject.2 As stated by Clarke, the pioneering work of Byrd was given prominent mention, by being the first of several studies on intercessory prayer employing a prospective, randomised, double-blind protocol.

Clarke and Jackson question the ethics of not declaring authors’ religious affiliations. This factor (along with other personal factors not listed as “competing interests”, such as race, sex and age) should not influence the clarity, objectivity, and validity of peer-reviewed scientific publications, nor impair the authors’ objectivity, integrity and performance as clinicians. Their concern about the legitimacy of citing biblical verse is also unfounded. The medical literature is replete with biblical citations. A recent publication on the topic of biblical origins of placebo3 is just one example from the MEDLINE database.

Straney expresses concern regarding the clinical relevance of prayer. More than 88% of the world’s populations believe in the supernatural,4 and prayer, being one of the oldest and most widely practised spiritual rituals, is frequently practised by patients when they have health problems.1 Knowing that patients commonly resort to prayer as a means of coping and finding meaning in life obliges clinicians to have some insight into how this practice affects patients’ health. Courses in spirituality and medicine are now offered in medical schools in the United States.5

In examining the relationship between belief in supernatural agents and mortality, Norenzayan and Hansen6 concluded: “our findings support the idea that belief in the supernatural agency is a core response to the human awareness of mortality” (original authors’ emphasis). Their conclusion supports the view that the spiritual search for meaning and hope in life is integral to human existence. Such exploration is virtually universal, albeit to varying degrees of depth, length and frequency.

The study by Benson et al that Straney alludes to as being absent from our article on prayer as medicine1 was in fact cited (reference 12) and discussed in the body of the text. Our article reviewed the plausible mechanisms by which prayer may benefit individuals who engage in the practice. The postulation of a mechanism of action does not imply an explanation of aetiology. For example, a postulation that the resolution of an infection occurs through bacterial mitotic inhibition would neither prove nor disprove that a particular antibiotic is the agent of healing. Thus, Huang’s contention that “belief in the existence of such a being [(God)] is itself the plausible mechanism . . . [and] should be . . . classified as a ‘placebo’ effect” is a naturalistic fallacy.

Grace cited data on religious affiliation and life expectancy among Australians. However, these data have not been subject to systematic and appropriate analysis for possible association. In contrast, religiosity was positively correlated with longevity among 10 000 Israelis over a 23-year period.7 Similar results were obtained in a 28-year follow-up of 5000 Californians.8 Religiosity was also shown to be an independent risk factor in a prospective study of over 300 elderly patients having cardiac surgery:9 compared with patients who reported preoperatively that they derived strength and comfort from their religious beliefs, those who didn’t were found to have a threefold greater risk of perioperative and 6-month mortality. Furthermore, a study of 34 000 Seventh-day Adventists in California10 revealed that they outlived other white male and female Californians by 7.3 and 4.4 years, respectively, giving them probably the highest life expectancy of any formally described population.

Improved health practices and social connection are probably factors that provide a causal link between religious affiliation and health or longevity. In an era of spiralling health care costs, the big picture is the potential public health implications of religiosity as a low-cost health measure. Individuals or bodies responsible for health care policy, budgeting and delivery should welcome further exploratory research into the preventive and therapeutic effects and cost-effectiveness of religious practice in health promotion within appropriate community settings.

In reply: The MJA’s spirituality and health supplement has reawakened the long-standing tension between supporters of science and supporters of spirituality, and I welcome their conflicting and unaccommodating views. The barrage of letters received reflects a perceived incongruity between spirituality and evidence-based medicine, with its requirement for evidence that is controlled, measured, counted and analysed by statistical methods.1 But the task of physicians has always been to understand not only the disease but also the patient. And for some patients, religion and spirituality are important — or, indeed, central — to their lives and health. The purpose of the supplement was to explore this area.

Jackson is perturbed that, in publishing the supplement, the Journal has sold its scientific soul. However, one of the goals of the Journal is to provide a scholarly forum for continuing education and informed debate on standards of clinical practice, ethics, and social, legal and other issues related to health care in Australia.2

While it must be acknowledged that religion and spirituality involve areas of knowledge not governed by the scientific method, it would be intellectually dishonest to refuse to consider any role for spirituality in health care.

Jackson also alleges that the supplement fails to satisfy the Journal’s policy on sponsored supplements, but proffers no evidence. In fact, the supplement complies completely with our policy for such publications.3

Despite the ongoing conflict between science and spirituality, exploration of the latter is increasingly considered for inclusion in modern medical curricula.