Associations between socioeconomic factors and proinflammatory cytokines in children, adolescents and young adults: a systematic review protocol

INTRODUCTION There is now substantial evidence of a social gradient in bone health. Social stressors, related to socioeconomic status, are suggested to produce an inflammatory response marked by increased levels of proinflammatory cytokines. Here we focus on the particular role in the years before the achievement of peak bone mass, encompassing childhood, adolescence and young adulthood. An examination of such associations will help explain how social factors such as occupation, level of education and income may affect later-life bone disorders. This paper presents the protocol for a systematic review of existing literature regarding associations between socioeconomic factors and proinflammatory cytokines in those aged 6-30 years. METHODS AND ANALYSIS We will conduct a systematic search of PubMed, OVID and CINAHL databases to identify articles that examine associations between socioeconomic factors and levels of proinflammatory cytokines, known to influence bone health, during childhood, adolescence or young adulthood. The findings of this review have implications for the equitable development of peak bone mass regardless of socioeconomic factors. Two independent reviewers will determine the eligibility of studies according to predetermined criteria, and studies will be assessed for methodological quality using a published scoring system. Should statistical heterogeneity be non-significant, we will conduct a meta-analysis; however, if heterogeneity prevent numerical syntheses, we will undertake a best-evidence analysis to determine whether socioeconomic differences exist in the levels of proinflammatory cytokines from childhood through to young adulthood. ETHICS AND DISSEMINATION This study will be a systematic review of published data, and thus ethics approval is not required. In addition to peer-reviewed publication, these findings will be presented at professional conferences in national and international arenas.