TY - JOUR
T1 - A systematic review and meta-analysis of longitudinal hippocampal atrophy in healthy human ageing
AU - Fraser, Mark A.
AU - Shaw, Marnie E.
AU - Cherbuin, Nicolas
N1 - Publisher Copyright:
© 2015 Elsevier Inc.
PY - 2015/5/5
Y1 - 2015/5/5
N2 - Introduction: This review aimed to produce hippocampal atrophy rate estimates from healthy ageing studies as well as control samples from observational studies across the adult lifespan which can be used as benchmarks to evaluate abnormal changes in pathological conditions. Methods: The review followed PRISMA guidelines. PUBMED (to February 2014) was searched for longitudinal MRI studies reporting hippocampal atrophy or volume change in cognitively healthy individuals. Titles were screened and non-English, duplicate or irrelevant entries were excluded. Remaining record abstracts were reviewed to identify studies for full text retrieval. Full text was retrieved and screened against inclusion/exclusion criteria. Bibliographies and previous reviews were examined to identify additional studies. Data were summarised using meta-analysis and age, segmentation technique and study type were tested as potential moderators using meta-regression. It was hypothesised that population studies would produce higher atrophy rates than clinical observational studies. Results: The systematic search identified 4410 entries and 119 studies were retrieved with 58 failing selection or quality criteria, 30 were excluded as multiple reports and 3 studies were unsuitable for meta-analysis. The remaining 28 studies were included in the meta-analysis, n. = 3422, 44.65% male, 11,735. person-years of follow-up, mean age was 24.50 to 83. years. Mean total hippocampal atrophy for the entire sample was 0.85% per year (95% CI 0.63, 1.07). Age based atrophy rates were 0.38% per year (CI 0.14, 0.62) for studies with mean age <. 55. years (n. = 413), 0.98% (CI 0.27, 1.70) for 55 to <. 70. years (n. = 426), and 1.12% (CI 0.86, 1.38) for ≥. 70. years (n. = 2583). Meta-regression indicated age was associated with increased atrophy rates of 0.0263% (CI 0.0146, 0.0379) per year and automated segmentation approaches were associated with a reduced atrophy rate of - 0.466% (CI - 0.841, - 0.090). Population studies were not associated with a significant effect on atrophy. Analyses of 11 studies separately measuring left and right hippocampal atrophy (n. = 1142) provided little evidence of laterality effects. While no study separately reported atrophy by gender, a number tested for gender effects and 2 studies reported higher atrophy in males. Conclusions: Hippocampal atrophy rates increase with age with the largest increases occurring from midlife onwards. Manual segmentation approaches result in higher measured atrophy rates.
AB - Introduction: This review aimed to produce hippocampal atrophy rate estimates from healthy ageing studies as well as control samples from observational studies across the adult lifespan which can be used as benchmarks to evaluate abnormal changes in pathological conditions. Methods: The review followed PRISMA guidelines. PUBMED (to February 2014) was searched for longitudinal MRI studies reporting hippocampal atrophy or volume change in cognitively healthy individuals. Titles were screened and non-English, duplicate or irrelevant entries were excluded. Remaining record abstracts were reviewed to identify studies for full text retrieval. Full text was retrieved and screened against inclusion/exclusion criteria. Bibliographies and previous reviews were examined to identify additional studies. Data were summarised using meta-analysis and age, segmentation technique and study type were tested as potential moderators using meta-regression. It was hypothesised that population studies would produce higher atrophy rates than clinical observational studies. Results: The systematic search identified 4410 entries and 119 studies were retrieved with 58 failing selection or quality criteria, 30 were excluded as multiple reports and 3 studies were unsuitable for meta-analysis. The remaining 28 studies were included in the meta-analysis, n. = 3422, 44.65% male, 11,735. person-years of follow-up, mean age was 24.50 to 83. years. Mean total hippocampal atrophy for the entire sample was 0.85% per year (95% CI 0.63, 1.07). Age based atrophy rates were 0.38% per year (CI 0.14, 0.62) for studies with mean age <. 55. years (n. = 413), 0.98% (CI 0.27, 1.70) for 55 to <. 70. years (n. = 426), and 1.12% (CI 0.86, 1.38) for ≥. 70. years (n. = 2583). Meta-regression indicated age was associated with increased atrophy rates of 0.0263% (CI 0.0146, 0.0379) per year and automated segmentation approaches were associated with a reduced atrophy rate of - 0.466% (CI - 0.841, - 0.090). Population studies were not associated with a significant effect on atrophy. Analyses of 11 studies separately measuring left and right hippocampal atrophy (n. = 1142) provided little evidence of laterality effects. While no study separately reported atrophy by gender, a number tested for gender effects and 2 studies reported higher atrophy in males. Conclusions: Hippocampal atrophy rates increase with age with the largest increases occurring from midlife onwards. Manual segmentation approaches result in higher measured atrophy rates.
KW - Ageing
KW - Controls
KW - Epidemiology
KW - Hippocampus
KW - Longitudinal
KW - MRI
UR - http://www.scopus.com/inward/record.url?scp=84937758572&partnerID=8YFLogxK
U2 - 10.1016/j.neuroimage.2015.03.035
DO - 10.1016/j.neuroimage.2015.03.035
M3 - Review article
SN - 1053-8119
VL - 112
SP - 364
EP - 374
JO - NeuroImage
JF - NeuroImage
ER -