Now, for some details.
--The study's results:
"Descriptive statistics for the study sample are presented in Table 1 (N = 268), including demographics, religious factors, covariates, and brain volumes.
"Table 2 presents longitudinal regression models of religious factors and covariates on change in left and right hippocampal volumes. Positive model coefficients indicate less atrophy over time.
"Reported life-changing religious experience at baseline was associated with greater atrophy between baseline and follow-up in the left and right hippocampus (left: b = −0.45, P<.001; right: b = −0.32, P = .012).
"Born-again Protestant group membership at baseline was associated with greater atrophy in the left and right hippocampus compared with non born-again Protestant group membership (left: b = −0.15, P = .046; right: b = −0.15, P = .050).
"Catholic group membership (n = 22) (b = −0.22, P = .046) and no religious group membership at baseline (n = 19) (b = −0.28, P = .046) were also associated with greater atrophy in the left hippocampus over time compared with non born-again Protestant group membership."
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The study's discussion of its results:
"The findings of this study indicate that certain religious factors may influence longitudinal change in hippocampal volume during late life. Greater hippocampal atrophy over time was predicted by baseline identification as born-again Protestants, Catholics, or no religious affiliation, compared with Protestants who were not born-again.
"Greater hippocampal atrophy was also predicted by reports at baseline of having had life-changing religious experiences. These longitudinal associations were not explained by baseline psychosocial or psychiatric factors (social support, stress, and depression status), demographic factors, duration in the study, or total baseline cerebral volume. Frequency of public and private religious activity did not predict changes in hippocampal volume.
"One way of interpreting these findings is within the context of the hypothesized impact of cumulative stress on the hippocampus. While some religious variables have been found to be associated with positive mental health . . . other religious factors may be a source of stress . . . . Research on biological pathways by which stress may influence hippocampal volumes has primarily explored neuronal death . . , decreased neurogenesis . . . , and dendritic retraction . . . .
"The glucocorticoid vulnerability hypothesis proposes that chronic stress alters the hippocampus by elevating levels of glucocorticoids, which in turn extends the time period during which the hippocampus is susceptible to damage from various sources . . . .
"The measure of stress used in this study was not correlated with changes in hippocampal volume, possibly due to the fact that it captured acute rather than cumulative stressors. Research indicates that relationships between stress and hippocampal volume likely operate at the level of cumulative rather than acute stress, leaving the cumulative stress framework a plausible interpretation of these results.
"Greater hippocampal atrophy was observed longitudinally in this study among born-again Protestants, Catholics, and those reporting no religious affiliation, compared with non born-again Protestants. These findings may reflect potential cumulative stress associated with being a member of a religious minority. Though religious factors have been associated with positive mental health . . . , studies have shown members of religious minority groups may also experience stressors related to these group affiliations . . . [.
"Greater hippocampal atrophy was also found to be longitudinally associated with reported life-changing religious experiences. Spiritual experiences not easily interpreted within an existing cognitive framework or set of religious beliefs have been shown in previous research to be detrimental to subjective well-being . . . . Such experiences have the capacity to produce doubts regarding previously unquestioned convictions, potentially inducing cumulative stress even if the experience was subjectively positive. If the experience prompts a change in religious groups, existing social networks may also be disrupted.
"Thus, as possible sources of cumulative stress, both minority religious group membership and life-changing religious experiences may contribute to conditions that are deleterious for hippocampal volume.
"These findings can be interpreted within the framework of previous studies identifying the hippocampus as a brain region potentially involved in religious or spiritual beliefs and practices. Using PET and MRI data, studies of meditation indicate that the hippocampus has been found to be activated during meditative states, compared to control states . . . . Structurally, among meditation practitioners (compared to non-practitioner controls), significantly larger volumes . . . , and higher gray matter concentrations . . . have been found in regions activated during meditation, including the right hippocampus.
"The current study did not find an association between change in hippocampal volume and frequency of spiritual activities, possibly reflecting the potential of varying spiritual practices to affect neuroanatomy differently.
"Research on temporal lobe epilepsy indicates that features of hyper-religiosity may be positively associated with hippocampal atrophy, but findings are mixed . . . . Associations found in the current study between life-changing religious experiences (but not frequency of religious practices) and hippocampal atrophy are consistent with a previous finding that the content and intensity of religious experiences (but not frequency of religious activities), differed between regular churchgoers and temporal-lobe epilepsy patients with hyper-religious features . . . , symptoms linked to hippocampal atrophy in some studies."
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--The study describes its sample size as being "relatively large," not small, and, in fact, notes that its size is a strength of the study:
"The relatively large sample size, longitudinal design, and the assessment of a range of religious and psychosocial factors are strengths of this study.
"Limitations include the geographically and religiously constrained nature of the sample (largely Southeastern Protestant Christians), as well as the small sample size of participants reporting a life-changing religious experience. The image acquisition used in this study is also limited to the technology available when it began in 1994, which was retained throughout the study in order to have comparable scans for longitudinal analyses. Future research on qualitative aspects of life-changing religious experiences could provide critical insight into the particular features of religion underlying the observed relationships with hippocampal volume.
"In addition, comprehensive cognitive testing in future studies could help determine the role of cognitive performance in both late life religious experiences and hippocampal volume."
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The study's implications:
"This study is among the first to examine religious and spiritual correlates of structural neuroanatomy, identifying several understudied factors associated with hippocampal atrophy. Religious factors, including religious group membership and life-changing religious experiences, but not frequency of public and private religious practices, were longitudinally associated with hippocampal atrophy.
"Atrophy in this region has important clinical implications, having been identified as a marker of late life mental health problems such as depression . . . and dementia . . . . These results may reflect an impact of cumulative stress on hippocampal volume. Mechanisms for these results, such as the elucidation of potential glucocorticoid stress pathways leading to atrophy, need to be more clearly identified, making the interpretation of these findings necessarily speculative. Future research exploring neuroanatomical changes in late life should not overlook the potential impact of religious factors, which remain relevant for a substantial proportion of the US population."
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Finally, Koenig's actual contributions to the study:
Koenig is not listed in the study's acknowledgments as having conceived or designed any of the study's experiments. (Cynthia Key of the Duke Neuropsychiatric Imaging Research Laboratory provided the hippocampal measurements).
Nor is Koenig listed as having performed the study's experiments or analyzed the study's data.
Nor is Koenig listed as having provided any reagents, materials or analysis tools for the study.
Koenig is listed, however (along with three others) as having written the study's manuscript.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0017006Edited 11 time(s). Last edit at 03/24/2012 07:18PM by steve benson.