To systematically review the literature with the primary aim of identifying behavioural interventions to improve vitamin D stores in children from at-risk ethnic groups.

Review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PROSPERO registration number: CRD42017080932. Health Behaviour Model and Behaviour Change Wheel framework constructs used to underpin evaluation of interventions. Methodological quality evaluated using Cochrane Risk of Bias, Cochrane ROBINS-I and NHLBI tools.

Databases Cochrane Library, MEDLINE, EMBASE, CINAHL with secondary search of Google Scholar. No country limits set. Papers between January 1990 and February 2018, published in English included. Anticipating study heterogeneity, outcome measures not pre-specified and identified from individual full papers. Updated literature search November 2020.

Patient or population including pregnant women, newborns and children aged under 18 years, from Asian or African ethnic groups.

Of 10 690 articles screened, 298 underwent full-text review, with 24 ultimately included for data extraction. All identified studies conducted a vitamin D pharmacological supplementation intervention, with two also incorporating a behavioural intervention strategy. No study explicitly defined a primary aim of evaluating a behavioural intervention, undertaken to study its effect on vitamin D supplement uptake.

There is a need to address the paucity of data in ethnic at-risk children on how behavioural interventions ideally developed and co-produced with the community under study, affect and help improve vitamin D uptake, within the antenatal and pregnancy phase as well as during childhood.

In the current climate of an ageing population, it is imperative to identify preventive measures for dementia.

We implemented a multifaceted index of cognitive reserve markers and investigated dementia incidence over 15 years of follow-up in a representative sample of the English population.

Data were 12 280 participants aged ≥50 years from the English Longitudinal Study of Ageing, free from dementia at their baseline assessments during wave 1 (2002–2003), 3 (2006–2007) or 4 (2008–2009), and followed up until wave 8 (2016–2017). The Cognitive Reserve Index was constructed as a composite measure of education, occupation and leisure activities, using a standardised questionnaire. Cox proportional hazards regression models were used to estimate the hazard ratios of dementia in relation to cognitive reserve levels (low, medium and high) and its components (education, occupation and leisure activities).

During the follow-up period, 602 participants aged 56–99 years developed dementia. Higher levels of cognitive reserve (hazard ratio 0.65, 95% CI 0.48–0.89, P = 0.008) were associated with a lower risk of dementia. An individual analysis of its components showed that higher levels of education (hazard ratio 0.56, 95% CI 0.36–0.88, P = 0.012), occupation (hazard ratio 0.72, 95% CI 0.56–0.91, P = 0.008) and leisure activities (hazard ratio 0.74, 95% CI 0.56–0.99, P = 0.047) were predictive of a reduced dementia risk, with the first two components particularly protective in younger participants (<85 years).

This study showed a reduced risk of dementia for individuals with a higher level of cognitive reserve, represented by higher education, complex occupations and multifaceted level of leisure activities.