BackgroundScoping reviews are used to identify knowledge gaps, set research agendas, and identify implications for decision-making. The conduct and reporting of scoping reviews is inconsistent in the literature. We conducted a scoping review to identify: papers that utilized and/or described scoping review methods; guidelines for reporting scoping reviews; and studies that assessed the quality of reporting of scoping reviews.MethodsWe searched nine electronic databases for published and unpublished literature scoping review papers, scoping review methodology, and reporting guidance for scoping reviews. Two independent reviewers screened citations for inclusion. Data abstraction was performed by one reviewer and verified by a second reviewer. Quantitative (e.g. frequencies of methods) and qualitative (i.e. content analysis of the methods) syntheses were conducted.ResultsAfter searching 1525 citations and 874 full-text papers, 516 articles were included, of which 494 were scoping reviews. The 494 scoping reviews were disseminated between 1999 and 2014, with 45 % published after 2012. Most of the scoping reviews were conducted in North America (53 %) or Europe (38 %), and reported a public source of funding (64 %). The number of studies included in the scoping reviews ranged from 1 to 2600 (mean of 118). Using the Joanna Briggs Institute methodology guidance for scoping reviews, only 13 % of the scoping reviews reported the use of a protocol, 36 % used two reviewers for selecting citations for inclusion, 29 % used two reviewers for full-text screening, 30 % used two reviewers for data charting, and 43 % used a pre-defined charting form. In most cases, the results of the scoping review were used to identify evidence gaps (85 %), provide recommendations for future research (84 %), or identify strengths and limitations (69 %). We did not identify any guidelines for reporting scoping reviews or studies that assessed the quality of scoping review reporting.ConclusionThe number of scoping reviews conducted per year has steadily increased since 2012. Scoping reviews are used to inform research agendas and identify implications for policy or practice. As such, improvements in reporting and conduct are imperative. Further research on scoping review methodology is warranted, and in particular, there is need for a guideline to standardize reporting.Electronic supplementary materialThe online version of this article (doi:10.1186/s12874-016-0116-4) contains supplementary material, which is available to authorized users.

O lder adults experiencing memory and cognition deficits without substantial limitations in activities of daily living may be given a diagnosis of mild cognitive impairment.1 These patients often present with subjective memory loss, impairment of cognitive function and no change in their basic daily functioning. Mild cognitive impairment has recently been recognized as a distinct condition, with a prevalence that ranges from 3% to 42% and increases with age.2 Because of the growing proportion of older adults worldwide, the prevalence of this condition will only increase in the future.3 Each year, 3%-17% of people with mild cognitive impairment experience progression to dementia, 4-6 a rate that increases to between 11% and 33% by 2 years after the initial diagnosis.7 More than 4.6 million new cases of dementia are diagnosed each year, 3 and efforts to reduce this public health burden are essential. Strategies to delay the progression of mild cognitive impairment are being sought to meet this challenge.One strategy that has been hypothesized to delay the progression from mild cognitive impairment to dementia is the use of cognitive enhancers, agents that are often used to treat dementia. These medications include cholinesterase inhibitors (e.g., donepezil, rivastigmine and galantamine) and the N-methyl-d-aspartic acid receptor antagonist memantine.8 donepezil, rivastigmine and galantamine increase the concentration of acetylcholine at neurotransmitter sites, 9 enhancing the brain's cholinergic function. Galantamine also influences activity at nicotinic receptors, 9 whereas memantine modulates the neurotransmitter glutamate. We conducted a systematic review to examine the efficacy and safety of cognitive enhancers for mild cognitive impairment.

Organochlorine chemicals and polychlorinated biphenyls (PCBs) have been suspected as possible risk factors for non-Hodgkin lymphoma (NHL). We investigated PCBs and organochlorine pesticides and risk of NHL in a population-based case-control study in British Columbia, Canada. Congeners of PCBs (including dioxinlike congeners) and pesticides or pesticide metabolites were measured in plasma of 422 pretreatment cases and 460 control subjects. This is so far the largest study to examine organochlorines in plasma to date. Several dioxin-like PCB congeners were associated with increased risk of NHL, including dioxin-like PCB nos. 118 and 156 with odds ratios (OR) for the highest versus lowest quartile between 1.6 and 1.8. Several non-dioxin-like congeners also showed significant associations. The PCB congener with the strongest association was no. 180 with an OR for the highest versus the lowest quartile of 1.83 (95% confidence interval 5 1.18-2.84). Six pesticide analytes also showed a significant association with NHL; b-hexachlorocyclohexane, p,p 0 -DDE, hexachlorobenzene, mirex, oxychlordane and trans-nonachlor. The strongest association was found for oxychlordane, a metabolite of the pesticide chlordane (highest vs. lowest quartile OR 5 2.68, 95% confidence interval 5 1.69-4.24). Our results provide further evidence that organochlorines contribute to NHL risk. ' 2007 Wiley-Liss, Inc.