Effect of obstructive sleep apnoea on diabetic retinopathy and maculopathy: a systematic review and meta-analysis

AIMS

To summarize the association between obstructive sleep apnoea and diabetic retinopathy and diabetic maculopathy, and to examine the effects of oxygen desaturation index, mean and minimum oxygen saturation and time spent with < 90% oxygen saturation on diabetic retinopathy and diabetic maculopathy.

METHODS

A systematic search was performed for papers published from inception to January 2014 in MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews using indexed terms and free text. Additional searches were carried out for grey literature. Two authors conducted the study selection and quality assessment. Data extraction was performed by the main author and checked by the other authors.

RESULTS

One cohort study and 15 cross-sectional studies were included for narrative synthesis and three for meta-analyses. There was no convincing evidence that obstructive sleep apnoea was associated with diabetic retinopathy, although some evidence suggested that obstructive sleep apnoea was associated with greater severity of diabetic retinopathy and advanced diabetic retinopathy in people with Type 2 diabetes. Only six studies examined the impact of obstructive sleep apnoea on diabetic maculopathy and our narrative review suggests there is an association in Type 2 diabetes. Oxygen desaturation index, mean oxygen saturation or time spent with < 90% oxygen saturation were not associated with diabetic retinopathy, and insufficient evidence was available to draw conclusions on their effects on diabetic maculopathy; however, there was evidence from both narrative synthesis and meta-analysis that minimum oxygen saturation had an impact on diabetic retinopathy (pooled odds ratio 0.91, 95% CI 0.87-0.95; I(2) = 0%).

CONCLUSIONS

There is a need for large cohort studies with long-term follow-up data to examine the long-term effects of obstructive sleep apnoea and other sleep variables on advanced retinal disease in diabetes.

The Association between Obstructive Sleep Apnea on Diabetic Kidney Disease: A Systematic Review and Meta-Analysis

STUDY OBJECTIVE

This systematic review aims to investigate the association between obstructive sleep apnea (OSA) and diabetic kidney disease (DKD).

METHODS

MeSH terms and free text searches were performed on MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from inception to April 2015. Zetoc and OpenGrey databases were queried for grey literature, and lastly, hand searches were carried out. Study selection and quality assessment were conducted by two authors. One author carried out data extraction, which was checked by other authors. The relationships between apneahypopnea index (AHI), oxygen desaturation index (ODI), time spent under 90% oxygen saturation (%TST < 90), and minimum and mean oxygen saturation (O2) on DKD were examined.

RESULTS

Two longitudinal and ten cross-sectional studies were included for our narrative synthesis, and seven studies for meta-analysis. Studies that performed multi-variable analysis demonstrated significant associations between OSA (assessed using either apnea-hypopnea index or ODI) and DKD in type 2 diabetes mellitus (T2DM). This was confirmed by meta-analysis (pooled OR 1.73, 95% CI: 1.13-2.64). There was some evidence to suggest that %TST < 90 may have an association with DKD. There was insufficient evidence to conclude on the relationship between minimum and mean oxygen saturation on DKD. There was no evidence available on the associations between OSA and other respiratory parameters in type 1 diabetes mellitus populations.

CONCLUSIONS

There is moderate evidence that OSA is associated with DKD in patients with T2DM. Large prospective studies with long-term follow up are needed to assess the possible bi-directional mechanisms between OSA and DKD.

Health allowance for improving the nutritional status and development of 3-5-year-old left-behind children in poor rural areas of China: study protocol for a cluster randomised trial

Background

Left-behind children (LBC) are recognised as a new social group in China. LBC are young children who are abandoned in rural villages whilst their parents travel to distant urban centres for employment (a new generation of migrant workers). Following the rapid growth in the number of migrant workers, the LBC population is also rapidly increasing. These children are usually left to be raised by elderly grandparents, a single parent, or sometimes distant relatives or neighbours who have limited resources, tend to have a poor education and sometimes are in frail health. Over 40 % of the 61 million LBC in China who are under 5 years old are undernourished, which affects their long-term health and abilities. An intervention that combines a conditional cash transfer (CCT) with nutrition education offers a potential solution.

Methods/Design

A cluster randomised controlled trial design will be used to allocate 40 villages to the intervention arm (20 villages) or control arm (20 villages). The caregivers and all of the 3–5-year-old LBC will be the target population. Caregivers in the intervention arm will receive a cash allowance conditional on attending nutrition education sessions, ensuring that the LBC will use basic public health services over a 12-month period. At the baseline, midterm (month 6) and end (month 12) of the intervention period, evaluations will be conducted in all 40 villages. Multilevel generalised linear models will be used to analyse the impact of the intervention on nutrition status and other outcomes, adjusting for baseline levels using an analysis of covariance approach. The cost of the intervention will also be estimated.

Discussion

If found to be cost-effective, the findings will inform the development of a sustainable model to improve nutrition status among LBC in rural areas of China.

Trial registration

Chinese Trial Register (ChiCTR) identifier: CTXY-140003-2. Registered on 19 Aug 2014.

The role of grandparents in childhood obesity in China - evidence from a mixed methods study

BACKGROUND

The current literature on the influences of family environment on childhood obesity is predominantly based on western populations and has focused on the role of parents. This study examined the influence of grandparents on the development of obesity among Chinese primary school aged children.

METHODS

A mixed methods study was conducted in four socioeconomically distinct primary school communities in two cities of southern China. The qualitative study (17 focus groups and four personal interviews) involved parents, grandparents, school staff, and food retailers in the vicinity of the schools (n = 99) and explored perceived causes of childhood obesity. The cross-sectional study examined the association between children's objectively measured weight status and reported health behaviours, and the presence and role of grandparents in the household. It included children from three randomly selected third grade (8 to 10 years) classes from each school (n = 497).

RESULTS

Grandparents were commonly perceived to contribute to childhood obesity through inappropriate perception (e.g. fat children are healthy and well cared for), knowledge (e.g. obesity related diseases can only happen in adults; the higher the dietary energy/fat content, the more nutritious the food), and behaviour (e.g. overfeeding and indulging through excusing the children from household chores). Conflicting child care beliefs and practices between grandparents and parents, and between grandparents and school teachers, were felt to undermine efforts to promote healthy behaviours in children. In the cross-sectional study, children who were mainly cared for by their grandparents were more likely to be overweight/obese (adjusted OR = 2.03; 95 % CI = 1.19 to 3.47); and to consume more sugar-added drinks and unhealthy snacks (B = 2.13, 95 % CI = 0.87 to 3.40), than children who were mainly cared for by their parents or other adult. Children who lived with two or more grandparents in the household were more likely to be overweight/obese than children who did not live with any grandparent (adjusted OR = 1.72; 95 % CI = 1.00 to 2.94).

CONCLUSIONS

Involvement of grandparents in childcare is an important factor contributing to childhood obesity in China. Future preventive interventions should include strategies that target grandparents.

Supported self-management for patients with COPD who have recently been discharged from hospital: a systematic review and meta-analysis

PURPOSE

Although many hospitals promote self-management to chronic obstructive pulmonary disease (COPD) patients post discharge from hospital, the clinical effectiveness of this is unknown. We undertook a systematic review of the evidence as part of a Health Technology Assessment review.

METHODS

A comprehensive search strategy with no language restrictions was conducted across relevant databases from inception to May 2012. Randomized controlled trials of patients with COPD, recently discharged from hospital after an acute exacerbation and comparing a self-management intervention with control, usual care or other intervention were included. Study selection, data extraction, and risk of bias assessment were undertaken by two reviewers independently.

RESULTS

Of 13,559 citations, 836 full texts were reviewed with nine randomized controlled trials finally included in quantitative syntheses. Interventions were heterogeneous. Five trials assessed highly supported multi-component interventions and four trials were less supported with fewer contacts with health care professionals and mainly home-based interventions. Total sample size was 1,466 (range 33-464 per trial) with length of follow-up 2-12 months. Trials varied in quality; poor patient follow-up and poor reporting was common. No evidence of effect in favor of self-management support was observed for all-cause mortality (pooled hazard ratio =1.07; 95% confidence interval [0.74 to 1.55]; I (2)=0.0%, [n=5 trials]). No clear evidence of effect on all-cause hospital admissions was observed (hazard ratio 0.88 [0.61, 1.27] I (2)=66.0%). Improvements in St George's Respiratory Questionnaire score were seen in favor of self-management interventions (mean difference =3.84 [1.29 to 6.40]; I (2)=14.6%), although patient follow-up rates were low.

CONCLUSION

There is insufficient evidence to support self-management interventions post-discharge. There is a need for good quality primary research to identify effective approaches.

TargetCOPD: a pragmatic randomised controlled trial of targeted case finding for COPD versus routine practice in primary care: protocol

BACKGROUND

Many people with clinically significant chronic obstructive pulmonary disease (COPD) remain undiagnosed worldwide. There are a number of small studies which have examined possible methods of case finding through primary care, but no large RCTs that have adequately assessed the most cost-effective approach.

METHODS/DESIGN

In this study, using a cluster randomised controlled trial (RCT) in 56 general practices in the West Midlands, we plan to investigate the effectiveness and cost-effectiveness of a Targeted approach to case finding for COPD compared with routine practice. Using an individual patient RCT nested in the Targeted arm, we plan also to compare the effectiveness and cost-effectiveness of Active case finding using a postal questionnaire (with supplementary opportunistic questionnaires), and Opportunistic-only case finding during routine surgery consultations.All ever-smoking patients aged 40-79 years, without a current diagnosis of COPD and registered with participating practices will be eligible. Patients in the Targeted arm who report positive respiratory symptoms (chronic cough or phlegm, wheeze or dyspnoea) using a brief questionnaire will be invited for further spirometric assessment to ascertain whether they have COPD or not. Post-bronchodilator spirometry will be conducted to ATS standards using an Easy One spirometer by trained research assistants.The primary outcomes will be new cases of COPD and cost per new case identified, comparing targeted case finding with routine care, and two types of targeted case finding (active versus opportunistic). A multilevel logistic regression model will be used to model the probability of detecting a new case of COPD for each treatment arm, with clustering of patients (by practice and household) accounted for using a multi-level structure.A trial-based analysis will be undertaken using costs and outcomes collected during the trial. Secondary outcomes include the feasibility, efficiency, long-term cost-effectiveness, patient and primary care staff views of each approach.

DISCUSSION

This will be the largest RCT of its kind, and should inform how best to identify undiagnosed patients with COPD in the UK and other similar healthcare systems. Sensitivity analyses will help local policy-makers decide which sub-groups of the population to target first.

TRIAL REGISTRATION

Current controlled trials ISRCTN14930255.

Hypoxemia and glycemic control in type 2 diabetes mellitus with extreme obesity

CONTEXT

Obstructive sleep apnea (OSA) has been shown to be associated with type 2 diabetes mellitus (DM). Studies on healthy individuals found that OSA is associated with lower insulin sensitivity. We hypothesized that nocturnal hypoxemia from OSA is associated with poorer glycemia in severely obese DM individuals.

DESIGN AND SETTING

This was a retrospective observational study of 122 non-DM, 126 non-insulin-treated DM, and 35 insulin-treated DM patients. Data were collected on demographic characteristics, body mass index, and comorbidities. An overnight sleep study was performed in all patients, and OSA was defined as an apnea-hypopnea index of ≥5 events/h.

RESULTS

There were more males (P = .003) and a lower proportion of white Europeans (P = .010) among DM patients. The prevalence of OSA was 80.1% in DM and 63.1% in non-DM individuals (P = .001). DM individuals also had lower oxygen saturation (O2) (P = .0106), greater percentage of time spent under 90% oxygen saturation (%TST<90%) (P = .0067), and higher apnea-hypopnea index (P = .0085). Regression analysis showed that %TST<90% and minimum O2 saturations were associated with worse hemoglobin A1c results among DM individuals. Every 10% reduction in minimum O2 was associated with a 0.3% increase in HbA1c, whereas a 10% increase in %TST<90% was associated with a 0.2% increase in hemoglobin A1c after adjusting for a range of potential confounders.

CONCLUSION

The high OSA prevalence in DM individuals and a positive relationship between nocturnal hypoxemia and glycemia supports the need to assess correction of hypoxemia as a management strategy for glycemic control.

Mental health and asthma in China: the Guangzhou Biobank Cohort Study

BACKGROUND

There is consistent evidence of the co-occurrence of poor mental health and asthma in Western populations. Since the experience and expression of mental health is partly culturally determined, it is of interest to examine if similar associations are found in other cultural settings. In that regard, very little is known about the association between mental health and asthma in Asian countries, such as China.

PURPOSE

The aim of this study was to investigate the relationship between mental health and asthma in a large sample from China.

METHOD

We used data from the Guangzhou Biobank Cohort Study phase 3 (n = 9,280). Participants reported physician-diagnosed asthma. Mental health measures included the 15-item Chinese version of the Geriatric Depression Scale (GDS-C) and the SF-12 Mental Component Summary (MCS) score. We compared the prevalence of asthma by GDS-C and MCS scores by estimating prevalence ratios (PRs) and their corresponding 95% confidence intervals (95% CI), using Poisson regression.

RESULTS

Compared to those without depression, the prevalence of asthma was higher in those with moderate or severe depression levels (PR = 2.63, 95% CI = 1.58–4.40 and PR = 4.43, 95% CI = 1.62–12.09, p for trend ≤0.0001). The prevalence of asthma increased by 46% with every 1 standard deviation increase of the GDS-C score (PR = 1.46, 95% CI = 1.24–1.73). The MCS score was not associated with asthma.

CONCLUSION

Depressive symptoms were associated with asthma prevalence in a Chinese population. Further research into the mechanism and potential directions of causality is warranted.

Preventing childhood obesity, phase II feasibility study focusing on South Asians: BEACHeS

OBJECTIVE

To assess feasibility and acceptability of a multifaceted, culturally appropriate intervention for preventing obesity in South Asian children, and to obtain data to inform sample size for a definitive trial.

DESIGN

Phase II feasibility study of a complex intervention.

SETTING

8 primary schools in inner city Birmingham, UK, within populations that are predominantly South Asian.

PARTICIPANTS

1090 children aged 6-8 years took part in the intervention. 571 (85.9% from South Asian background) underwent baseline measures. 85.5% (n=488) were followed up 2 years later.

INTERVENTIONS

The 1-year intervention consisted of school-based and family-based activities, targeting dietary and physical activity behaviours. The intervention was modified and refined throughout the period of delivery.

MAIN OUTCOME MEASURES

Acceptability and feasibility of the intervention and of measurements required to assess outcomes in a definitive trial. The difference in body mass index (BMI) z-score between arms was used to inform sample size calculations for a definitive trial.

RESULTS

Some intervention components (increasing school physical activity opportunities, family cooking skills workshops, signposting of local leisure facilities and attending day event at a football club) were feasible and acceptable. Other components were acceptable, but not feasible. Promoting walking groups was neither acceptable nor feasible. At follow-up, children in the intervention compared with the control group were less likely to be obese (OR 0.41; 0.19 to 0.89), and had lower adjusted BMI z-score (-0.15 kg/m(2); 95% CI -0.27 to -0.03).

CONCLUSIONS

The feasibility study informed components for an intervention programme. The favourable direction of outcome for weight status in the intervention group supports the need for a definitive trial. A cluster randomised controlled trial is now underway to assess the clinical and cost-effectiveness of the intervention.

TRIAL REGISTRATION NUMBER

ISRCTN51016370.

Contributors to childhood obesity in Iran: the views of parents and school staff

OBJECTIVE

To explore the contextual influences on childhood obesity in Tehran, Iran to inform future development of an obesity prevention intervention for Iranian primary school children.

STUDY DESIGN

Qualitative study.

METHODS

Focus groups and interviews with parents and school staff were convened to explore their perceptions of the causes of childhood obesity. Eleven focus groups and three interviews were held with parents and school staff (88 participants in total) from three different socio-economic areas in Iran's capital city, Tehran. All the discussions were transcribed verbatim in Persian. An iterative thematic approach was used for data analysis.

RESULTS

Overall, the causes of childhood obesity were perceived to relate to macro-level policy influences, the school environment, sociocultural factors, and family and individual behavioural factors, acting in combination. A key emergent theme was the pervasive influence of Government policies on children's food intake and physical activity. Another key theme was the political and sociocultural context that does not support girls and women in Iran in having active lifestyles.

CONCLUSION

The findings suggest that parents and school staff have sophisticated views on the possible causes of childhood overweight and obesity which encompassed behavioural, structural and social causes. A prominent emerging theme was the need for state level intervention and support for a healthy environment. Any local initiatives in Iran are unlikely to be successful without such support.

WHAT IS KNOWN ON THIS SUBJECT

Childhood obesity is growing in Iran and it is seen as one of the features of the nutrition transition in developing countries. Findings from cross-sectional studies suggest a range of lifestyle factors contribute to obesity in the Iranian population.

WHAT THIS STUDY ADDS

This qualitative study explores the socioenvironmental changes contributing to childhood obesity in primary school-aged children in Iran. Findings have provided important contextual data on the perceived contributors to childhood obesity in Iran, such as macro-level policy influences on accessibility to healthy food and physical activity, competing priorities at school level, sociocultural influences on diet and physical activity and limited knowledge and skills of parents. This has laid the foundation for the development of appropriate childhood obesity prevention interventions.

The views of stakeholders on the role of the primary school in preventing childhood obesity: a qualitative systematic review

Schools are increasingly recognized as an ideal setting for interventions to tackle childhood obesity. A better understanding of the views of key stakeholders would help to engage schools and inform the feasibility of such interventions in practice. This meta-synthesis of 18 qualitative studies explores the views of parents, school staff, school governors, school nurses and students on the role of the primary school in preventing childhood obesity. Six categories emerged: 'School as a key setting'; 'What schools should be doing to promote healthy eating (HE)'; 'What schools should be doing to promote physical activity (PA)'; 'General barriers'; 'Barriers to promoting HE at school'; and 'Barriers to promoting PA at school'. Thirty-seven finer-level themes emerged within these categories. Stakeholders agreed on the key role of the primary school as a setting for obesity prevention, the importance of schools providing and promoting opportunities for HE and PA, and the need for schools to work with parents. Some perceived barriers could be overcome at school level, e.g. using unhealthy foods as rewards/fundraisers or withholding PA for bad behaviour. Leadership and guidance from government were considered to be needed to counteract other observed barriers, particularly regarding school canteens, support for parents and time for PA.

Development of a childhood obesity prevention programme with a focus on UK South Asian communities

OBJECTIVE

We report the development of a childhood obesity prevention intervention for UK South Asian primary school-aged children, guided by the UK Medical Research Council (MRC) framework for complex intervention development and evaluation.

METHODS

We combined information gained from a literature review, stakeholder focus groups, an expert group, review of local resources and mapping to the Analysis Grid for Environments Linked to Obesity (ANGELO framework) in an intervention development process. The study took place in 2007 in Birmingham, UK.

RESULTS

Contextual information from the stakeholder focus groups was essential for informing intervention development. The expert group defined guiding principles for the intervention. Informing intervention design by assessing existing local resources addressed intervention sustainability. The use of the ANGELO framework ensured a comprehensive environmental approach to intervention development. The intervention consisted of two broad processes; increasing children's physical activity levels through school, and increasing skills of families through activity-based learning. The developed intervention is being evaluated in a major study.

CONCLUSIONS

The intervention development process has resulted in a tailored intervention programme to prevent childhood obesity in UK South Asian communities, but also intervention processes that could be applied to other communities and tailored to local context.

Past dust and GAS/FUME exposure and COPD in Chinese: the Guangzhou Biobank Cohort Study

The impact of occupational dust and gas/fume exposure on chronic obstructive pulmonary disease (COPD) in developing countries has not been quantified. We examined the relationship between past dust and fume exposure and prevalence of COPD and respiratory symptoms in a cross-sectional analysis of a large Chinese population sample. Participants in the Guangzhou Biobank Cohort Study (n = 8216; 27.3% men, mean age 61.9 ± 6.8 years) had spirometry and a structured interview including exposures, symptoms, and lifestyle. Self-reported intensity and duration of dust and gas/fume exposure was used to derive cumulative exposure. COPD was diagnosed from spirometry using lower limit of normal based on prediction equations. COPD was associated with high exposure to dust or gas/fume (exposed: 87/1206 v non-exposed: 191/3853; adjusted odds ratio: 1.41; 95% confidence interval (CI) 1.06, 1.87) with no evidence of effect modification by smoking. Respiratory symptoms were associated with exposures to dust and gas/fume, with adjusted odds ratios for chronic cough/phlegm of 1.57 (1.13, 2.17) and 1.39 (1.20, 1.60) for dyspnoea. The overall population attributable fraction for COPD due to occupational exposure was 10.4% (95% CI -0.9%, 19.5%). Occupational dust and gas/fume exposure is associated with an increased prevalence of COPD in this Chinese sample, independent of smoking. The population attributable fraction in Chinese is similar to that in Western populations.

Sex, susceptibility to smoking and chronic obstructive pulmonary disease: the effect of different diagnostic criteria. Analysis of the Health Survey for England

BACKGROUND

Some previous studies suggest there are sex differences in susceptibility to, and prevalence of, chronic obstructive pulmonary disease (COPD) but findings are inconsistent. In this study, whether different diagnostic criteria for COPD may contribute to these conflicting findings was examined.

METHODS

Cross sectional analysis of data from the 1995, 1996 and 2001 Health Survey for England was undertaken, including participants of white ethnicity, aged 40+ years with a valid smoking history and lung function data. COPD was defined using Global Initiative for Chronic Obstructive Lung Disease (GOLD), National Institute for Health and Clinical Excellence (NICE) and lower limit of normal (LLN) spirometric criteria, in the absence of a diagnosis of asthma.

RESULTS

COPD was present in 3035 (16.1%), 1304 (7.0%) and 1684 (9.0%) people, according to the GOLD, NICE and LLN criteria, respectively. With both the GOLD and NICE definitions, men had significant independent increased risks of COPD compared with women (OR 1.46 (95% CI 1.34 to 1.59) and 1.30 (1.15 to 1.48), respectively). With the LLN definition, this effect was removed (OR 0.96 (0.87 to 1.07). With the use of both the GOLD and NICE criteria, women had significantly greater susceptibility to COPD (25-30% higher risk) for the same level of pack years of exposure. This was not observed with the LLN criteria.

CONCLUSIONS

The study indicates that sex differences in risk of COPD reported in previous studies are influenced by the definition used for COPD. When using a statistically driven definition (LLN), no independent sex difference was found and there was no evidence of an increased susceptibility to COPD among female compared with male smokers.