Sign up for Weekday J and get the latest on what's happening in the Jewish Bay Area.

JERUSALEM — Here's an interesting fact. Bnei Brak, which may be Israel's most religious city, also has the highest average life expectancy: 81.1 years for women and 77.4 years for men.

What makes that finding even more curious is that Bnei Brak, outside Tel Aviv, also happens to be Israel's poorest city, thus confounding the expected correlation between increased wealth and health. Moreover, rates of smoking among males remain high, and even a casual glance around the streets of Bnei Brak will serve to establish that news of the benefits of exercise and a low-fat diet has not yet reached most of it inhabitants.

A growing body of scientific evidence suggests the key to the longevity of Bnei Brak residents may well be their religiousness. Fully three-quarters of the 300 studies to date of the relationship between religious belief and health have shown a positive correlation. Various studies have shown that religious belief and regular attendance at religious services is associated with reduced doctors' visits, a reduced incidence of certain forms of cancer and heart disease, and lower post-operative mortality and quicker rates of recovery.

The Harvard Health News Letter recently devoted a full issue to the impact of religiousness on health and courses in healing and spirituality are proliferating in American medical schools.

While none of the studies conducted to date can establish a causal link between religious belief and improved health, the associations shown are sufficient to give pause. A Duke University study showed that those who attend religious services once a week are half as likely to have elevated blood levels of interleukin-6, which is associated with some cancers and heart disease.

A 1995 Dartmouth Medical School study of 232 patients recovering from open-heart surgery found that none of the 37 patients who described themselves as deeply religious died over the first six months, while 21, or 10 percent, of the rest did. Those who received strong community support reinforced by strong religious belief were 14 times as likely to survive as those who had neither.

One California study, conducted over 28 years and published in 1997, found that those who attended religious services weekly had a one-third lower death rate. (Orthodox Jewish men pray three times daily and Orthodox women one or more times a day.)

Even in the presence of a strong community support structure, religious belief appears to have an independent salutary effect. A study comparing residents of kibbutzim with those of religious communities in Israel over 16 years found that the religious community had consistently lower mortality rates for the entire period.

Certainly, some correlation between faith and improved health can be explained by factors not unique to religious observance, including healthier lifestyles, greater community support, reduced rates of stress and a more upbeat, optimistic attitude. Nevertheless, at least one finding has completely stumped the scientists: Two Duke University researchers presented a study to the American Heart Association on 150 patients suffering from acute heart disease. Those patients who were prayed for did significantly better than those who were not prayed for, even when the patient was completely unaware that he or she was being prayed for.

There is also a close correlation between depression and higher mortality rates among older people. The large family-size in the Orthodox community and the great stress on the mitzvah of honoring one's parents help ensures that Bnei Brak's elderly receive frequent visits from several generations of descendants. That experience gives them the constant satisfaction of witnessing their own continuity.

In addition, from an early age, the primary mental activity of most Bnei Brak males is talmudic study, and they continue to learn all their lives, even after they have retired from other pursuits. It is not unusual to see hundreds of young men in their 20s eagerly hanging on the talmudic discourses of Torah sages in their late 80s or even 90s, with both sides shouting back and forth in vigorous debate. The constant source of intellectual stimulation provided by Torah study helps preserve mental acuity and with it life satisfaction.

Finally, Orthodox Jews have much higher rates of marriage and lower rates of divorce, and there is an abundance of evidence establishing the positive effects of marriage on health. Nine of 10 married men alive at 48 will make it to 65. The comparable figure for never married men is six out of 10, and divorced and widowed men fare only slightly better.

Of course, no number of studies establishing a correlation between religious belief and health can provide that faith to those who lack it. But those who already possess that faith seem to don't need to be convinced that it serves them well.