Lower limb amputation in England: prevalence, regional variation and relationship with revascularisation, deprivation and risk factors. A retrospective review of hospital data

OBJECTIVE

We describe the prevalence of major lower limb amputation across England and its relationship with revascularisation, patient demography and disease risk factors.

DESIGN

Retrospective cohort study.

SETTING

England 1 April 2003 to 31 March 2009.

PARTICIPANTS

Patients aged 50-84 years.

MAIN OUTCOME MEASURES

Age standardised prevalence rates were calculated using Hospital Episode Statistics as the numerator with census data as the denominator. The outcome measure 'amputation with revascularisation' was created if an amputation could be linked with a revascularisation. Logistic regression determined the odds of having an amputation with a revascularisation across England. Regression was performed unadjusted and repeated after controlling for demographic (age, sex, social deprivation) and disease risk factors (diabetes, hypertension, coronary heart disease, cerebrovascular disease, smoking).

RESULTS

There were 25,312 amputations and 136,215 revascularisations, and 7543 cases were linked. The prevalence rate per 100,000 (95% confidence intervals) for amputation was 26.3 (26.0-26.6) with rates significantly higher in Northern England (North: 31.7; 31.0-32.3, Midlands: 26.0; 25.3-26.7, South: 23.1; 22.6-23.5). The revascularisation rate was 141.6 (140.8-142.3) with significantly higher rates again in Northern England (North: 182.1; 180.5-183.7, Midlands: 121.3; 119.8-122.9, South 124.9; 123.9-125.8). The odds of having an amputation with a revascularisation remained significantly higher in the North (OR 1.22; 1.13-1.33) even after controlling demographic and disease risk factors.

CONCLUSIONS

There is a North-South divide in England for both major lower limb amputation and revascularisation. The higher odds of having an amputation with a revascularisation in the North were not fully explained by greater levels of deprivation or disease risk factors.

Sleep duration and memory in the elderly Chinese: longitudinal analysis of the Guangzhou Biobank Cohort Study

STUDY OBJECTIVES

Previous cross-sectional studies showed that short or long sleep duration was associated with memory impairment (MI), but longitudinal studies are scarce. We examined whether sleep duration was associated with memory decline or development of MI.

DESIGN SETTING PARTICIPANTS

We conducted a prospective analysis based on the Guangzhou Biobank Cohort Study on 13,888 participants aged 50+ years without MI at baseline and with a follow-up for a mean of 4.1 years.

MEASURES AND RESULTS

Memory decline was assessed using the Delayed 10-Word Recall Test (DWRT), and in a subset (n = 6,020) with the Mini-Mental State Examination (MMSE). Short and long sleep duration was defined as ≤ 5 hours/day and ≥ 9 hours/day, respectively. Data were analyzed both continuously for memory decline and dichotomously for MI (independently defined as DWRT, < 4; MMSE, < 25). After adjusting for multiple potential confounders, both short and long sleep durations were associated with memory decline using DWRT or MMSE score changes (all P < 0.001). Seven percent (n = 980) developed DWRT-defined MI and 4.0% (n = 194) MMSE-defined MI during the follow-up. Only those with a short (≤ 5 h/day) sleep duration had a significantly increased risk of DWRT-defined MI (odds ratio = 1.53 (95% confidence interval; 1.21-1.93); P < 0.001) relative to normal sleepers (7 h/day). The association remained significant after excluding those with poor self-reported health. No associations were observed with MMSE-defined MI for both long and short sleep durations.

CONCLUSIONS

This is the largest study to date addressing the association between extremes of sleep duration and memory decline. The observed adverse relationships provide support for an intervention study to examine the potential benefits of normalizing sleep duration in attenuating memory decline.

Long-term risk of cardiovascular disease among type 2 diabetic patients with asymptomatic intracranial atherosclerosis: a prospective cohort study

OBJECTIVE

To investigate whether asymptomatic middle cerebral artery (MCA) stenosis is associated with risk of cardiovascular disease (CVD) in Chinese with type 2 diabetes.

METHODS

In this prospective cohort study, 2,144 Hong Kong Chinese with type 2 diabetes and without history of stroke or atrial fibrillation were recruited in 1994-1996 and followed up for a median of 14.51 years. Participants were assessed at baseline for MCA stenosis using transcranial Doppler. We performed survival analysis to assess the association between asymptomatic MCA stenosis and first CVD event, defined as ischemic stroke, acute coronary syndrome (ACS) or cardiovascular death.

RESULTS

Of the 2,144 subjects, MCA stenosis at baseline was detected in 264 (12.3%). Rates of stroke, ACS and cardiovascular death per 100 were, respectively, 2.24, 2.92 and 1.11 among participants with stenosis, higher than among those without stenosis. Ten-year cumulative occurrence of stroke, ACS and cardiovascular death in subjects with MCA stenosis was 20%, 24% and 10%, respectively, higher than the corresponding values for subjects without stenosis(all P<0.001). After adjusting for covariates, MCA stenosis was found to be an independent predictor of stroke [hazard ratio (HR) 1.40, 95%CI 1.05-1.86; P = 0.02], ACS (HR 1.35, 95%CI 1.04-1.75; P = 0.02) and cardiovascular death(HR 1.56, 95%CI 1.04-2.33; P = 0.03).

CONCLUSIONS

Asymptomatic MCA stenosis is a risk factor for CVD in Chinese with type 2 diabetes, and detection of asymptomatic MCA stenosis by transcranial Doppler can identify diabetic individuals at high risk of future CVD. This finding is particularly important for diabetic individuals in Asia, where intracranial atherosclerosis is common.

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.

The impact of hypoxemia on nephropathy in extremely obese patients with type 2 diabetes mellitus

STUDY OBJECTIVES

Diabetes mellitus (DM) is associated with obstructive sleep apnea (OSA) and nephropathy. The hypoxemia associated with OSA may exacerbate renal deterioration in DM nephropathy. We examined the role of hypoxemia in the development of DM nephropathy in severely obese patients.

METHODS

This cross-sectional study examined anonymized data from 90 DM patients with extreme obesity attending a weight management service. All patients underwent a routine overnight sleep study. Respiratory parameters measured included apnea-hypopnea index (AHI), mean and minimum oxygen (O2) saturations, and time spent under 90% O2 saturation (%TST < 90%). Chronic kidney disease (CKD+) was defined as estimated glomerular filtration rate (eGFR) ≤ 60 mL/min/1.73 m(2).

RESULTS

Twenty (22%) patients were CKD+. These patients were 7 years older (mean age ± SD 57 ± 11 years, p = 0.003) and had greater adiposity (mean body mass index [BMI] ± SD 50.6 ± 8.7 kg/m(2), p = 0.012). No significant differences were found for median AHI and minimum O2 saturation. %TST < 90% was 4 times greater in CKD+ group (p = 0.046). Multivariate regression analysis showed that AHI (β = -0.17, 95% CI: -0.316 to -0.024) and %TST < 90% (β = -0.215, 95% CI: -0.406 to -0.023) were negatively correlated with eGFR after adjustment for age, gender, BMI, comorbidities, insulin treatment, and drugs affecting the renin-angiotensin system. No associations were found between mean and minimum O2 saturations, and eGFR.

CONCLUSION

Apnea and hypopnea events as well as duration of nocturnal hypoxemia were inversely associated with renal function after adjusting for potential confounders. Given the significant burden of renal disease in diabetes, greater vigilance is required in identifying OSA in DM patients with extreme obesity.

A three-stage genome-wide association study combining multilocus test and gene expression analysis for young-onset hypertension in Taiwan Han Chinese

BACKGROUND

Although many large-scale genome-wide association studies (GWASs) have been performed, only a few studies have successfully identified replicable, large-impact hypertension loci; even fewer studies have been done on Chinese subjects. Young-onset hypertension (YOH) is considered to be a more promising target disorder to investigate than late-onset hypertension because of its stronger genetic component.

METHODS

To map YOH genetic variants, we performed a 3-stage study combining 1st-stage multilocus GWASs, 2nd-stage gene expression analysis, and 3rd-stage multilocus confirmatory study.

RESULTS

In the 1st stage, Illumina550K data from 400 case-control pairs were used, and 22 genes flanked by 14 single nucleotide polymorphism (SNP) septets (P values adjusted for false discovery rate (pFDR) < 3.16×10(-7)) were identified. In the 2nd stage, differential gene expression analysis was carried out for these genes, and 5 genes were selected (pFDR < 0.05). In the 3rd stage, we re-examined the finding with an independent set of 592 case-control pairs and with the joint samples (n = 992 case-control pairs). A total of 6 SNP septets flanking C1orf135, GSN, LARS, and ACTN4 remained significant in all 3 stages. Among them, the same septet flanking ACTN4 was also associated with blood pressure traits in the Hong Kong Hypertension Study (HKHS) and in the Wellcome Trust Case-Control Consortium Hypertension Study (WTCCCHS). LARS was detected in the HKHS, but not in the WTCCCHS. GSN may be specific to Taiwanese individuals because it was not found by either the HKHS or the WTCCCHS.

CONCLUSIONS

Our study identified 4 previously unknown YOH loci in Han Chinese. Identification of these genes enriches the hypertension susceptibility gene list, thereby shedding light on the etiology of hypertension in Han Chinese.

Influence of Alzheimer's disease genes on cognitive decline: the Guangzhou Biobank Cohort Study

Cognitive decline is a reduction in cognitive ability usually associated with aging, and those with more extreme cognitive decline either have or are at risk of progressing to mild cognitive impairment and dementia including Alzheimer's disease (AD). We hypothesized that genetic variants predisposing to AD should be predictive of cognitive decline in elderly individuals. We selected 1325 subjects with extreme cognitive decline and 1083 well-matched control subjects from the Guangzhou Biobank Cohort Study in which more than 30,000 southern Chinese older people have been recruited and followed up. Thirty single-nucleotide polymorphisms in 29 AD-associated genes were genotyped. No statistically significant allelic associations with cognitive decline were found by individual variant analysis. At the level of genotypic association, we confirmed that the APOE ε4 homozygote significantly accelerated cognitive decline and found that carriers of the ACE rs1800764_C allele were more likely to show cognitive decline than noncarriers, particularly in those without college education. However, these effects do not survive after multiple testing corrections, and together they only explain 1.7% of the phenotypic variance in cognitive score change. This study suggests that AD risk variants and/or genes are not powerful predictors of cognitive decline in our Chinese sample.

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.

The association between adiposity, mental well-being, and quality of life in extreme obesity

OBJECTIVES

To explore the cross-sectional association between adiposity, mental well-being, and quality of life in extreme obese individuals entering a UK specialist weight management service prior to treatment commencement.

METHODS

The sample comprised 263 extreme obese individuals who were referred to the service as a result of having a body mass index (BMI) ≥40 kg/m2 or ≥35 kg/m2 with a co-morbid health condition. In a retrospective analysis, routinely collected baseline clinical examination data and self-report questionnaires (Impact of Weight on Quality of Life: IWQOL-Lite, EQ5D-3L, and Hospital Anxiety and Depression Scale: HADS) were analysed to examine the cross-sectional association between adiposity and quality of life.

RESULTS

The sample was predominantly female (74.8%) with mean BMI 47.0±7.9 kg/m2. Increasing adiposity was significantly negatively associated with quality of life, with an increase of 1 BMI unit associated with decreases of 1.93 in physical function (95% CI -2.86 - -1.00, p<0.001), 1.62 in self-esteem (95% CI -2.67 - -0.57, p<0.05), 2.69 in public distress (95% CI -3.75 - -1.62, p<0.001), 1.33 in work (95% CI -2.63 - -0.02, p<0.05), and 1.79 in total IWQOL-Lite scores (95% CI -2.65 - -0.93, p<0.001). Adiposity was associated with significantly increased risk of problems in mobility (OR = 3.44, 95% CI 1.47-8.05), and performing usual activities (OR = 2.45, 95% CI 1.10-5.46) in highest relative to lowest BMI tertile. The prevalence of experience of symptoms of anxiety (70.3%) and depression (66.2%) as measured by HADS was consistently high.

CONCLUSIONS

We identified a high prevalence of psychological co-morbidity, including widespread experience of symptoms of anxiety and depressive disorders and reduced quality of life among these extreme obese individuals seeking weight management treatment. Clinical implications include the need for the incorporation of strategies to improve mental well-being into multi-disciplinary weight management interventions.

Adverse lifestyle leads to an annual excess of 2 million deaths in China

Background

Adverse lifestyle factors have been associated with increased mortality, but data are lacking on their combined effect in developing populations, which we address in the present study.

Methods

In a death registry-based, case-control study among Hong Kong Chinese aged 30+y, proxy-reported lifestyle factors 10 y ago were collected for 21,363 cases (81% of all deaths) and 12,048 living controls. Risks associated with poor diet, inactivity, heavy alcohol intake, and smoking for all-cause and cause-specific mortality, adjusting for potential confounders, were determined, and excess deaths for the Chinese population were calculated.

Results

Adjusted odds ratios for all-cause mortality were 1.15 (95% CI 1.09, 1.23), 1.34 (1.27, 1.43), 1.36 (1.21, 1.52), and 1.58 (1.46, 1.70) for poor diet, inactivity, heavy alcohol intake and smoking, respectively. Increasing numbers of adverse lifestyle factors were associated with a dose-dependent increase in adjusted odds ratios of 1.30 (1.20, 1.40), 1.67 (1.54, 1.81), 2.32 (2.08, 2.60), and 3.85 (3.12, 4.75) for 1, 2, 3, and 4 risk factors relative to those with none. The population attributable fraction for all-cause, all-CVD and all-cancer mortality were 26.6%, 15.0%, and 32.1%, resulting in an excess of 2,017,541; 489,884; and 607,517 deaths annually, respectively. Although smoking was associated with the greatest excess loss of life (867,530), heavy drinking (680,466), and physical inactivity (678,317) were similarly important.

Conclusion

Adverse lifestyle factors contribute to one quarter of all deaths in China. Improving lifestyle practices, particularly focussing on moderating alcohol intake and increasing activity, and smoking cessation are critical to reducing the lifestyle-associated health burden.

Breastfeeding practice, oral contraceptive use and risk of rheumatoid arthritis among Chinese women: the Guangzhou Biobank Cohort Study

OBJECTIVE

Hormonal and reproductive factors are implicated in the aetiology of RA, but results of previous studies have been mixed. The aim of this cross-sectional study was to assess the relationships between RA, use of oral contraceptives (OCs) and history of breastfeeding in a population of older women from South China.

METHODS

We used baseline data from 7349 women ≥ 50 years of age in the Guangzhou Biobank Cohort. Questionnaires were used to obtain socio-demographic, lifestyle and obstetric history data, including parity, OC use and breastfeeding practices. The main outcome was RA. Women were asked about history of RA and were examined to assess joint swelling. RF levels were measured. The presence of RA was defined in two ways: (i) as reporting physician-diagnosed RA or pain and swelling in at least three joints (including the wrist), and (ii) also having at least one of the following: positive RF, morning stiffness or objective swelling of the small joints of the hands.

RESULTS

Compared with those who had never breastfed, breastfeeding was associated with half the risk of RA. The risk was lower with increasing duration of breastfeeding [adjusted odds ratio (OR) 0.54 (95% CI 0.29, 1.01) for breastfeeding at least 36 months; P for trend = 0.04]. OC use had no relationship with RA.

CONCLUSION

Breastfeeding (especially longer duration) but not OC use is associated with a lower risk of RA. This has potentially important implications for future RA disease burden, given the declining rates of breastfeeding and the one-child policy in China. Further research is needed to explain the biological mechanism.

A review of dietary influences on cardiovascular health: part 2: dietary patterns

Dietary recommendations are key to cardiovascular disease (CVD) management. The underpinning evidence is generally based on data generated from single nutrient or food types. However, food is not consumed in such a manner, and components may interact synergistically or antagonistically depending on the dietary composition. Analyses of dietary patterns have attempted to address these important issues. The aim of this review is to present the current evidence on three major dietary patterns and their relationship with CVD. The most widely reported is the Mediterranean diet, which is characterised by abundant use of olive oil, and plant-based foods, moderate consumption of fish, dairy products, alcohol with meals, and a relatively low intake of red meat. The strongest evidence of causality has been established for the Mediterranean diet and unlike other dietary patterns has been shown to significantly reduce major CVD events. The Dietary Approach to Stop Hypertension (DASH), emphasising fruit, vegetables and low fat dairy products, has successfully been shown to lower blood pressure and cholesterol levels. However, its true effects on CVD under freeliving conditions have yet to be fully explored. The available evidence is encouraging for CVD prevention, but long-term effectiveness is unclear. Very low-carbohydrate diets appear to exert their favourable effect on CVD risk factors via weight loss. However, longterm effectiveness and safety remains unclear. The available evidence supports the role of the DASH and Mediterranean diets in the prevention of CVD.

Associations between specific technologies and adolescent sleep quantity, sleep quality, and parasomnias

OBJECTIVE

We tested the hypothesis that weekday bedtime use of six technologies would be significantly associated with eight sleep parameters studied relating to sleep quantity, sleep quality, and parasomnias.

METHODS

In our cross-sectional study, we previously administered validated age-appropriate questionnaires (School Sleep Habits Survey, Technology Use Questionnaire). Participating adolescents (n=738; 54.5% boys) were aged 11-13 years and were from the Midlands region of the United Kingdom in 2010.

RESULTS

Frequent use of all technology types was significantly inversely associated with weekday sleep duration (hours). Frequent music listeners and video gamers had significantly prolonged sleep onset (β=7.03 [standard error {SE}, 2.66]; P<.01 and β=6.17 [SE, 2.42]; P<.05, respectively). Frequent early awakening was significantly associated with frequent use of all technology types. The greatest effect was observed in frequent television viewers (odds ratio [OR], 4.05 [95% confidence interval {CI}, 2.06-7.98]). Difficulty falling asleep was significantly associated with frequent mobile telephone use, video gaming, and social networking, with music listeners demonstrating the greatest effect (OR, 2.85 [95%CI, 1.58-5.13]). Music listeners were at increased risk for frequent nightmares (OR, 2.02 [95% CI, 1.22-3.45]). Frequent use of all technologies except for music and mobile telephones was significantly associated with greater cognitive difficulty in shutting off. Frequent television viewers were almost four times more likely to report higher sleepwalking frequency (OR, 3.70 [95% CI, 1.89-7.27]).

CONCLUSIONS

Frequent weekday technology use at bedtime was associated with significant adverse effects on multiple sleep parameters. If confirmed in other samples and longitudinally, improving sleep hygiene through better management of technology could enhance the health and well-being of adolescent populations.

The complex associations among sleep quality, anxiety-depression, and quality of life in patients with extreme obesity

INTRODUCTION

Sleep duration and quality have been associated with obesity. Sleep disturbance has been reported to be associated with stress and depression among non-obese populations, but these relationships have not been previously examined in the obese population. The objective of the current study was to examine the complex associations among sleep disturbance, quality of life, anxiety, and depression in a patient sample with severe obesity.

METHODS

Two hundred seventy consecutively recruited patients with a mean body mass index (BMI) of 47.0 kg/m² were studied. The correlation coefficient, multiple linear regressions, and structural equation modeling (SEM) analysis were used to evaluate the association between the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Impact of Weight on Quality of Life-Lite (IWQOL-Lite) and Hospital Anxiety and Depression Scale (HADS).

RESULTS

The mean (standard deviation; SD) PSQI score was 8.59 (5.11), and mean ESS score was 8.84 (5.79). After controlling for potential confounders, poor sleep quality and excessive daytime sleepiness were found to be significantly associated of all the components of IWQOL-Lite; physical function (β = -0.32, β = -0.27; P < 0.01), self-esteem (β = -0.23, β = -0.30; P < 0.05), sexual-life (β = -0.30, β = -0.35; P < 0.05), public distress (β = -0.39, β = -0.39; P < 0.01), and work (β = -0.26, β = -0.48; P < 0.01). We also found that the PSQI global score had a positive significant association with anxiety (β = 0.29; P = 0.01) and depression (β = 0.31; P = 0.01) components of HADS.

CONCLUSION

Poor sleep quality was strongly associated with mood disturbance and poor quality of life among extremely obese patients. Future interventions are needed to address sleep disturbance to prevent further development of psychological co-morbidity and potentially worsening of obesity among these individuals.

A review of dietary influences on cardiovascular health: part 1: the role of dietary nutrients

BACKGROUND

Lifestyle modification, including diet, is a key strategy for prevention and regression of cardiovascular disease (CVD), a leading cause of death worldwide. Traditionally, the study of the relationship between diet and CVD has focused on the analysis of single nutrients, or foods, in relation to CVD risk.

OBJECTIVE

In part one of this review, we present current epidemiologic and clinical evidence on nutrition and cardiovascular health with regards to specific foods and nutrients aimed at preventing CVD.

METHODS

The Cochrane Library database between 2006 and 2012 was searched for studies on effects of dietary factors on cardiovascular health.

DISCUSSION

Evidence is presented on soy protein, fats, fish, nuts, fruit, vegetables, electrolytes, vitamins, and carbohydrate including fibre, glycaemic index, and wholegrains. Evidence from specific foods underpins current dietary CVD prevention guidelines, that advise on replacing saturated with unsaturated fat, consuming carbohydrate foods that are wholegrain or of low glycaemic index, increased consumption of fruit, vegetables (particularly cruciferous), nuts, and oily fish. Other nutrients (such as soya protein, or reducing sodium intake) reduce CVD risk via favourable effects on disease contributors (such as LDL-cholesterol or blood pressure), but also infer/promote dietary change that impacts other nutrients (using less animal or processed foods, resulting in saturated fat reduction). The complexity and limitations of interpreting dietary epidemiologic studies is reviewed. With the general ineffectiveness of nutrient-based intervention, recently the shift has been towards the examination of associations between dietary patterns and cardiovascular health, which will be examined in the second part of this review.

The complexity of obesity in U.K. adolescents: relationships with quantity and type of technology, sleep duration and quality, academic performance and aspiration

BACKGROUND

Contemporary technology and multiple device use may link to increased body mass index (BMI). The sleep-obesity relationship is inconsistent in adolescents. Sleep duration and quality may have crucial connections to obesity development, particularly in adolescents where sleep alterations are common. Elevated BMI in adolescents may influence academic performance and aspiration, but data are limited.

OBJECTIVES

The objectives of this study was to assess the linear associations between BMI z-score and (i) quantity/type of technology used; (ii) sleep quantity/quality and (iii) academic performance/aspiration.

METHODS

Consenting adolescents (n = 624; 64.9% girls, aged 11-18 years) were recruited. The Schools Sleep Habits Survey and Technology Use Questionnaire were administered. Objective measures of height/weight were obtained.

RESULTS

Quantity of technology was positively associated with BMI z-score β = 0.10, P < 0.01. Those who always engaged in video gaming had significantly higher BMI z-score vs. never-users, β = 1.00, P < 0.001. Weekday sleep duration and sleep onset latency were related to BMI z-score, β = -0.24, P < 0.001 and β = 0.01, P < 0.001, respectively. An inverse linear association was observed between BMI z-score and academic performance, β = -0.68, P < 0.001.

CONCLUSIONS

If confirmed prospectively, reducing bedtime use of technology and improving sleep hygiene in adolescents could be an achievable intervention for attenuating obesity with potentially positive effects on academic performance.

Effectiveness of lifestyle interventions on obstructive sleep apnea (OSA): systematic review and meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is a common sleep disorder associated with several adverse health outcomes. Given the close association between OSA and obesity, lifestyle and dietary interventions are commonly recommended to patients, but the evidence for their impact on OSA has not been systematically examined.

OBJECTIVES

To conduct a systematic review and meta-analysis to assess the impact of weight loss through diet and physical activity on measures of OSA: apnea-hypopnea index (AHI) and oxygen desaturation index of 4% (ODI4).

METHODS

A systematic search was performed to identify publications using Medline (1948-2011 week 40), EMBASE (from 1988-2011 week 40), and CINAHL (from 1982-2011 week 40). The inverse variance method was used to weight studies and the random effects model was used to analyze data.

RESULTS

Seven randomized controlled trials (519 participants) showed that weight reduction programs were associated with a decrease in AHI (-6.04 events/h [95% confidence interval -11.18, -0.90]) with substantial heterogeneity between studies (I(2) = 86%). Nine uncontrolled before-after studies (250 participants) showed a significant decrease in AHI (-12.26 events/h [95% confidence interval -18.51, -6.02]). Four uncontrolled before-after studies (97 participants) with ODI4 as outcome also showed a significant decrease in ODI4 (-18.91 episodes/h [95% confidence interval -23.40, -14.43]).

CONCLUSIONS

Published evidence suggests that weight loss through lifestyle and dietary interventions results in improvements in obstructive sleep apnea parameters, but is insufficient to normalize them. The changes in obstructive sleep apnea parameters could, however, be clinically relevant in some patients by reducing obstructive sleep apnea severity. These promising preliminary results need confirmation through larger randomized studies including more intensive weight loss approaches.

Alcohol consumption and electrocardiographic left ventricular hypertrophy and mediation by elevated blood pressure in older Chinese men: the Guangzhou Biobank Cohort Study

BACKGROUND

Chinese people have a markedly lower alcohol consumption than people in the West. Whether alcohol consumption at such levels is associated with left ventricular hypertrophy, and the role of blood pressure (BP) in this relationship is unclear. We investigated the association between alcohol consumption and electrocardiographic left ventricular hypertrophy (ECG-LVH) and the mediating role of BP in Chinese men aged ≥50 years.

METHODS AND RESULTS

A case-control analysis was conducted on baseline cross-sectional data from the community-based Guangzhou Biobank Cohort Study (2003-2008), using standard 12-lead resting electrocardiograms. By comparing 191 new ECG-LVH cases with 4311 controls, excessive drinking (>210 g/week) showed excess risks for ECG-LVH (odds ratio [OR] = 1.90, 95% confidence interval [CI] = 1.12-3.24), after adjusting for education, income, occupation, physical activity, smoking, body mass index, fasting glucose, triglyceride, total cholesterol, high-density lipoprotein cholesterol, BP, and antihypertensive medication. Mediation analysis showed a significant mediating effect of BP on the association between excessive drinking and ECG-LVH: systolic (31%) and diastolic (16%). After multivariate adjustment, no significant association was found between occasional drinking (<once/week: OR = 1.20, 95% CI = 0.80-1.80) and moderate drinking (≥once/week to ≤210 g/week: OR = 0.88, 95% CI = 0.53-1.47) with increased/decreased risk of ECG-LVH.

CONCLUSIONS

Alcohol consumption at >210 g/week in Chinese men is an independent risk factor for ECG-LVH. Low power prevented us from examining whether drinking at <once/week to ≤210 g/week is associated with decreased/increased risk of ECG-LVH. Elevated BP partially mediates between alcohol and ECG-LVH. A Mendelian randomization approach with a large sample size is warranted to determine the relations among alcohol consumption, BP, and LVH.

Incidence of cardiovascular diseases in an Iranian population: the Isfahan Cohort Study

INTRODUCTION

Accurate estimates of the incidence of  cardiovascular diseases (CVD) comprising of acute myocardial infarction (AMI), unstable angina pectoris (UAP), sudden cardiac death (SCD), and stroke are very important for public health. However, such information is scarce, especially for middle- and low-income countries. 

METHODS

The Isfahan Cohort Study (ICS) prospectively followed up 6504 individuals, 51.8% women, aged 35 years and over, 6323 initially free of CVD, from urban and rural areas in three districts in central Iran including Isfahan, Najafabad, and Arak. A panel of specialists in cardiology and neurology decided on the diagnosis of the occurred events based on patients' hospital records, verbal autopsy, and death certificates. 

RESULTS

After 32893 person-years of follow-up, 427 new cases of CVD events (229 in men) were registered. Confirmed cases of AMI, stroke, UAP, and SCD were 57, 43, 93, and 36 in men and 32, 48, 100, and 18 in women, respectively. The corresponding crude incidence rates were 352, 265, 352, and 220 per 100000 person-years in men and 186, 279, 584, and 104 in women, respectively. No significant differences were found in age at the time of events occurrence between men and women and between different event types except for SCD and stroke in women that in average the former occurred nine years later. CVD mortality rate was 331 per 100000 person-years in men and 203 in women. 

CONCLUSION

We found substantially high incidence rates for almost all CVDs and mortality. These findings need urgent consideration by health policy makers specifically for women.

Association of 25-hydroxyvitamin D with type 2 diabetes among patients undergoing coronary angiography: cross-sectional findings from the LUdwigshafen Risk and Cardiovascular Health (LURIC) Study

OBJECTIVE

Evidence suggests that vitamin D may protect against the onset of diabetes. However, the mechanisms underlying the role of vitamin D on glycaemic status are unclear and warrant further investigation. We sought to determine the relationship between serum 25-hydroxyvitamin D (25[OH]D) and glycaemic status among intermediate-to-high-risk patients scheduled for coronary angiography.

METHODS

Participants were 3316 male and female patients (mean ± SD age, 62·7 ± 10·6 years). Four categories were formed according to serum 25[OH]D levels. The association between serum 25[OH]D and diabetes was assessed using multivariable logistic regression.

RESULTS

Fasting and 2 h post-load glucose, HbA1c and the HOMA-IR indices diminished with increasing serum 25[OH]D levels (P < 0·001). However, no associations were observed between insulin, pro-insulin or C-peptide and serum 25[OH]D concentrations. The pro-inflammatory markers IL-6 and hs-CRP also decreased considerably with higher vitamin D levels (P < 0·001). After full adjustment, those with optimal serum 25[OH]D levels had a reduced odds for fasting diabetes (OR = 0·63; 95% CI, 0·46-0·86; Ptrend = 0·01), 2 h post-load diabetes (OR = 0·46; 95% CI, 0·29-0·74; Ptrend = 0·004), both fasting/2 h post-load diabetes (OR = 0·61; 95% CI, 0·42-0·87; Ptrend = 0·001) and all of the combined hyperglycaemic states (OR = 0·68; 95% CI, 0·52-0·80; Ptrend = 0·01).

CONCLUSIONS

Higher serum 25[OH]D levels were associated with better glycaemic status and lower inflammation. Should these observations be confirmed in future studies, vitamin D supplementation may prove a useful adjunct in attenuating the onset of diabetes.