Directed acyclic graphs (DAGs), which offer systematic representations of causal relationships, have become an established framework for the analysis of causal inference in epidemiology, often being used to determine covariate adjustment sets for minimizing confounding bias. DAGitty is a popular web application for drawing and analysing DAGs. Here we introduce the R package ‘dagitty’, which provides access to all of the capabilities of the DAGitty web application within the R platform for statistical computing, and also offers several new functions. We describe how the R package ‘dagitty’ can be used to: evaluate whether a DAG is consistent with the dataset it is intended to represent; enumerate ‘statistically equivalent’ but causally different DAGs; and identify exposure-outcome adjustment sets that are valid for causally different but statistically equivalent DAGs. This functionality enables epidemiologists to detect causal misspecifications in DAGs and make robust inferences that remain valid for a range of different DAGs. The R package ‘dagitty’ is available through the comprehensive R archive network (CRAN) at [https://cran.r-project.org/web/packages/dagitty/]. The source code is available on github at [https://github.com/jtextor/dagitty]. The web application ‘DAGitty’ is free software, licensed under the GNU general public licence (GPL) version 2 and is available at [http://dagitty.net/].

OBJECTIVE: Continuous glucose monitoring (CGM) is increasingly used to assess glucose control in diabetes. The objective was to examine how analysis of glucose data might improve our understanding of the role temporal glucose variation has on large-for-gestational-age (LGA) infants born to women with diabetes. RESEARCH DESIGN AND METHODS: Functional data analysis (FDA) was applied to 1.68 million glucose measurements from 759 measurement episodes, obtained from two previously published randomized controlled trials of CGM in pregnant women with diabetes. A total of 117 women with type 1 diabetes (n = 89) and type 2 diabetes (n = 28) who used repeated CGM during pregnancy were recruited from secondary care multidisciplinary obstetric clinics for diabetes in the U.K. and Denmark. LGA was defined as birth weight ≥90th percentile adjusted for sex and gestational age. RESULTS: A total of 54 of 117 (46%) women developed LGA. LGA was associated with lower mean glucose (7.0 vs. 7.1 mmol/L; P < 0.01) in trimester 1, with higher mean glucose in trimester 2 (7.0 vs. 6.7 mmol/L; P < 0.001) and trimester 3 (6.5 vs. 6.4 mmol/L; P < 0.01). FDA showed that glucose was significantly lower midmorning (0900–1100 h) and early evening (1900–2130 h) in trimester 1, significantly higher early morning (0330–0630 h) and throughout the afternoon (1130–1700 h) in trimester 2, and significantly higher during the evening (2030–2330 h) in trimester 3 in women whose infants were LGA. CONCLUSIONS: FDA of CGM data identified specific times of day that maternal glucose excursions were associated with LGA. It highlights trimester-specific differences, allowing treatment to be targeted to gestational glucose patterns.

Background: To explore the relationship between work, retirement and physical activity. Methods: Cross-sectional analyses of data from self-completed questionnaires by 6224 civil servants aged 45–69 years participating in phase 5 of the Whitehall II longitudinal study. Results: There appeared to be a dose–response relationship between hours worked and the prevalence of physical activity, with a lower prevalence of recommended physical activity amongst participants working full time (≥30 h/week), higher prevalence rates amongst those working part time (<30 h/week), and the highest rates amongst participants who were not working at all. Physical activity rates did not increase greatly amongst study participants who had retired from the Civil Service but had gone on to do further full-time work, however, the higher physical activity rates of participants working part time, or not at all, were further enhanced amongst those who had also retired. Conclusions: These findings suggest that full-time work is associated with lower rates of recommended physical activity levels in this cohort of middle-aged white-collar office workers. Lower grade occupations are also less likely to meet the recommended physical activity levels. While retirement is associated with higher rates of recommended physical activity levels, this benefit is evident amongst those who work part time, or not at all, during their retirement, for whom the benefits of retirement and lower working hours on rates of physical activity appear additive. The frequency of different types of physical activity is associated with different occupational grades, with more sport and gardening being done by the higher occupational grades. Key points

Inequitable healthcare access, experiences and outcomes across ethnic groups are of concern across many countries. Progress on this agenda appears limited in England given the apparently strong legal and policy framework. This disjuncture raises questions about how central government policy is translated into local services. Healthcare commissioning organisations are a potentially powerful influence on services, but have rarely been examined from an equity perspective. We undertook a mixed method exploration of English Primary Care Trust (PCT) commissioning in 2010-12, to identify barriers and enablers to commissioning that addresses ethnic healthcare inequities, employing:- in-depth interviews with 19 national Key Informants; documentation of 10 good practice examples; detailed case studies of three PCTs (70+ interviews; extensive observational work and documentary analysis); three national stakeholder workshops. We found limited and patchy attention to ethnic diversity and inequity within English healthcare commissioning. Marginalization of this agenda, along with ambivalence, a lack of clarity and limited confidence, perpetuated a reinforcing inter-play between individual managers, their organisational setting and the wider policy context. Despite the apparent contrary indications, ethnic equity was a peripheral concern within national healthcare policy; poorly aligned with other more dominant agendas. Locally, consideration of ethnicity was often treated as a matter of legal compliance rather than integral to understanding and meeting healthcare needs. Many managers and teams did not consider tackling ethnic healthcare inequities to be part-and-parcel of their job, lacked confidence and skills to do so, and questioned the legitimacy of such work. Our findings indicate the need to enhance the skills, confidence and competence of individual managers and commissioning teams and to improve organizational structures and processes that support attention to ethnic inequity. Greater political will and clearer national direction is also required to produce the system change needed to embed action on ethnic inequity within healthcare commissioning.

Race and ethnicity are imprecise markers of the genotypic and sociocultural determinants of health, argue the authors.