The researchers defined religion and spirituality as having emotional, behavioral and cognitive dimensions.
The three meta-analyses are published in Cancer - the peer-reviewed journal of the American Cancer Society.
"To date, this series of meta-analyses represents the most comprehensive summary and synthesis of a rapidly growing area of psychosocial oncology: the role of religion and spirituality for patients and survivors managing the experience of cancer," says Dr. John Salsman, of Wake Forest School of Medicine in Winston-Salem.
According to the authors of one of the three reviews, a recent poll found that around 59% of people around the world describe themselves as religious, regardless of whether they regularly attend religious services or not.
Many cancer patients find solace in religion and spirituality, with one survey reporting that 69% of cancer patients pray for their health, compared with only 45% of the general population in the US.
While great importance is placed on meeting the spiritual needs of patients with cancer, studies examining the effects of religion and spirituality on wellbeing have tended to report mixed results. To address this, researchers have analyzed all published studies in this area, conducting a series of three reviews that include data for over 44,000 patients.
Greater psychological distress associated with spiritual disconnection
One analysis focused on the effects of religion and spirituality on spiritual health. The researchers found that patients who reported greater overall religious belief were also likely to report better physical wellbeing and ability to perform their routine tasks - particularly if cancer could be integrated into their religion and spirituality.
"These relationships were particularly strong in patients who experienced greater emotional aspects of religion and spirituality, including a sense of meaning and purpose in life as well as a connection to a source larger than oneself," explains lead author Dr. Heather Jim, of the Moffitt Cancer Center in Tampa, FL.
However, no association was found between this suggested impact on physical health and behavioral aspects of religion such as prayer, meditation and attending religious services.
A second analysis looking at mental health reported that positive mental health was more strongly linked with the emotional aspects of religion and spirituality than the behavioral or cognitive aspects.
Dr. Salsman states that spiritual wellbeing was associated with less anxiety, depression or distress. "Also, greater levels of spiritual distress and a sense of disconnectedness with God or a religious community was associated with greater psychological distress or poorer emotional wellbeing," he adds.
Changes over time need to be explored by future studies
Finally, the third analysis examined the ability of patients to maintain their social roles and relationships while battling their illness. Lead author Allen Sherman, of the University of Arkansas for Medical Sciences in Little Rock, states that patients with stronger spiritual wellbeing, more positive perceptions of God or stronger beliefs reported better social health.
"In contrast," he says, "those who struggled with their faith fared more poorly."
Medical News Today asked Dr. Salsman whether any of the analyses allowed the researchers to derive causal explanations. Did greater religious and spiritual beliefs lead to better wellbeing? Or could it be the case that declines in wellbeing lead related declines in religious and spiritual belief? He explained the series' shortcomings:
"Unfortunately, the analyses do not allow us to derive causal explanations. The vast majority of published studies have been cross-sectional. There are simply too few longitudinal studies in this area - a real weakness of the field."
As such, the effects of the relationship could be bidirectional - religion and spirituality could influence health or health could influence religion and spirituality.
The review authors state that future research should examine how this relationship changes over time, and whether support services focusing on meeting the spiritual needs of patients have a beneficial effect on their wellbeing.
"In addition, some patients struggle with the religious or spiritual significance of their cancer, which is normal. How they resolve their struggle may impact their health, but more research is needed to better understand and support these patients," states Dr. Jim.
Religion and spirituality have been indicated by other studies to have a different impact on wellbeing, however. A study exploring the experiences of African-American women coping with infertility revealed that the experience for some was influenced by religion, with a sense of shame heightened by the belief that God intended women to bear children.