Self-reported seasonality is associated with complaints of sleep problems and deficient sleep duration: the Hordaland Health Study

Change in sleep duration dependent on time of year is a central characteristic of seasonal affective disorder (SAD). In a community health survey, we analysed associations between seasonality, subjective sleep problems and sleep duration. Totally, 8860 subjects (3531 men and 5329 women) aged between 40 and 44 years were included in the study. Seasonal changes in mood and behaviour were measured by the Global Seasonality Score (GSS) questionnaire, and subjects were grouped in high (GSS > or = 11), moderate (GSS 8-10) or low (GSS < 8) seasonality groups. Sleep symptomatology was assessed using a modified version of the Karolinska Sleep Questionnaire. Significant sleep duration deficiency was defined as the difference between subjective sleep need and sleep duration of at least 1 h. Sleep problems suggesting insomnia as well as increased daytime sleepiness were more prevalent in the high/moderate seasonality groups compared with the low seasonality group. Seasonality was furthermore associated with shorter sleep duration and increased subjective sleep need. Significant sleep duration deficiency was more prevalent in subjects reporting high (men 20% and women 21%) and moderate (men 13% and women 19%) seasonality than subjects reporting low (men 10% and women 14%) seasonality. In conclusion, we found seasonal changes in mood and behaviour to be associated with several sleep-related complaints. Sleep duration deficiency increased with increasing seasonality, mainly due to increasing subjective sleep need.     

Sleep complaints in middle‐aged women and men: the contribution of working conditions and work–family conflicts

This study aimed to examine how physical working conditions, psychosocial working conditions and work–family conflicts are associated with sleep complaints, and whether health behaviours explain these associations. We used pooled postal questionnaire surveys collected in 2001–2002 among 40–60‐year‐old employees of the City of Helsinki (n = 5819, response rate 66%). Participants were classified as having sleep complaints if they reported sleep complaints at least once a week on average (24% of women and 20% of men). Independent variables included environmental work exposures, physical workload, computer work, Karasek’s job strain and work–family conflicts. Age, marital status, occupational class, work arrangements, health behaviours and obesity were adjusted for. Most working conditions were associated strongly with sleep complaints after adjustment for age only. After adjustment for work–family conflicts, the associations somewhat attenuated. Work–family conflicts were also associated strongly with women’s [odds ratio (OR) 5.90; confidence interval (CI) 4.16–8.38] and men’s sleep (OR 2.56; CI 1.34–4.87). The associations remained robust even after controlling for unhealthy behaviours, obesity, health status, depression and medications. Physically strenuous working conditions, psychosocial job strain and work–family conflicts may increase sleep complaints. Efforts to support employees to cope with psychosocial stress and reach a better balance between paid work and family life might reduce sleep complaints. Sleep complaints need to be taken into account in worksite health promotion and occupational health care in order to reduce the burden of poor sleep.     

Short Sleep Duration as a Risk Factor for Hypercholesterolemia: Analyses of the National Longitudinal Study of Adolescent Health

Study Objectives:

To explore the relationship between sleep duration in adolescence and hypercholesterolemia in young adulthood. Experimental sleep restriction has been shown to significantly increase total cholesterol and LDL cholesterol levels in women. Short sleep duration has been found in cross sectional studies to be associated with higher total cholesterol and lower HDL cholesterol levels. Sleep deprivation could increase the risk for hypercholesterolemia by increasing appetite and dietary consumption of saturated fats, decreasing motivation to engage in regular physical activity, and increasing stress and resultant catecholamine induced lipolysis. No previous published population studies have examined the longitudinal relationship between sleep duration and high cholesterol.

Design:

Multivariate longitudinal analyses stratified by sex of the ADD Health using logistic regression.

Setting:

United States nationally representative, school-based, probability-based sample.

Participants:

Adolescents (n = 14,257) in grades 7 to 12 at baseline (1994-95) and ages 18 to 26 at follow-up (2001-02).

Measurements and Results:

Among females, each additional hour of sleep was associated with a significantly decreased odds of being diagnosed with high cholesterol in young adulthood (OR = 0.85, 95% CI 0.75-0.96) after controlling for covariates. Additional sleep was associated with decreased, yet not statistically significant, odds ratios for hypercholesterolemia in males (OR = 0.91, 95% CI 0.79-1.05).

Conclusions:

Short sleep durations in adolescent women could be a significant risk factor for high cholesterol. Interventions that lengthen sleep could potentially serve as treatments and as primary preventative measures for hypercholesterolemia.

Citation:

Gangwisch JE; Malaspina D; Babiss LA; Opler MG; Posner K; Shen S; Turner JB; Zammit GK; Ginsberg HN. Short sleep duration as a risk factor for hypercholesterolemia: analyses of the National Longitudinal Study of Adolescent Health.     

Sleep disturbances as a predictor of occupational injuries among public sector workers

The association between disturbed sleep and increased risk of occupational injury has been observed in several cross-sectional and case–control studies, but prospective evidence is lacking. We examined prospectively whether sleep disturbances predicted occupational injuries in a large population of Finnish public sector employees. A total of 48 598 employees working in 10 municipalities and 21 hospitals in various parts of Finland were included. Sleep disturbances were assessed with the four-item Jenkins Sleep Problems Scale. Records of sickness absence due to occupational injury during the year following the survey were obtained from employers' registers. A proportion (9076; 22%) of participants reported disturbed sleep, and 978 (2.4%) had a recorded occupational injury. After adjustment for socio-demographic characteristics, the odds ratio (OR) for occupational injury was 1.38 [95% confidence interval (CI) 1.02–1.87] times higher for men with experiences of disturbed sleep than for those without sleep disturbances, but not significant for women. Of the sub-dimensions of sleep disturbances, the OR for occupational injury was 1.69 (95% CI 1.26–2.26) for women with difficulties initiating sleep, but not significant for men. These associations remained after additional adjustment for work stress, sleep length, obesity, alcohol use and mental health. This study suggests that sleep disturbances are a significant predictor of occupational injuries even after accounting for a range of covariates.     

Sleep duration and sleep complaints and risk of myocardial infarction in middle-aged men and women from the general population: the MONICA/KORA Augsburg cohort study

STUDY OBJECTIVES: To examine gender-specific associations between sleep duration and sleep complaints and incident myocardial infarction (MI). DESIGN: Cohort study. SETTING: A representative population sample of middle-aged subjects in Germany. PARTICIPANTS: The study was based on 3508 men and 3388 women (aged 45 to 74 years) who participated in one of the 3 MONICA (Monitoring trends and determinants on cardiovascular diseases) Augsburg surveys between 1984 and 1995, who were free of MI and angina pectoris at baseline and were followed up until 2002. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: A total of 295 cases of incident MI among men and 85 among women occurred during a mean follow-up period of 10.1 years. Compared with women sleeping 8 hours, the multivariable adjusted hazard ratio (HR) of MI among women sleeping < or =5 hours was 2.98 (95% CI, 1.48-6.03), and among women sleeping > or =9 hours 1.40 (95% CI, 0.74-2.64); the corresponding HRs among men were 1.13 (95% CI, 0.66-1.92) and 1.07 (95% CI, 0.75-1.53). In multivariable analysis the relative risk of an incident MI for men and women with difficulties maintaining sleep was 1.12 (95% CI, 0.84-1.48) and 1.53 (95% CI, 0.99-2.37), respectively, and for men and women with difficulties initiating sleep the relative risk was 1.16 (95% CI, 0.82-1.63) and 1.30 (95% CI, 0.81-2.06), respectively. CONCLUSIONS: Modest associations between short sleep duration and difficulties maintaining sleep and incident MI were seen in middle-aged women but not men from the general population.     

Association of Short Sleep Duration with Weight Gain and Obesity at 1-Year Follow-Up: A Large-Scale Prospective Study

Study Objectives:

To investigate the association between short sleep duration and elevated body mass index (BMI) and obesity in a large sample of Japanese adults over a short period

Design:

Prospective design with baseline in 2006 and 1-year follow-up

Setting:

Workplaces of an electric power company in Japan

Participants:

35,247 company employees (31,477 men, 3,770 women) distributed throughout Japan

Measurements and Results:

Measured weight and height and self-reported sleep duration were obtained at annual health checkup in 2006 and 2007. Weight change was defined as the difference in body mass index (BMI) between the baseline and 1 year later. Relative to the reference category (sleep duration 7-8 h), short sleep duration (< 5 and 5-6 h) and long sleep duration ≥ 9 h were associated with an increased risk of weight gain among men after adjustment for covariates. Of the non-obese (BMI < 25) men at baseline, 5.8% became obese (BMI ≥ 25) 1 year later. Higher incidence of obesity was observed among the groups with shorter sleep duration. Adjusted odds ratios for the development of obesity were 1.91 (95%CI 1.36, 2.67) and 1.50 (95%CI 1.24, 1.80) in men who slept < 5 and 5-6 h, respectively. No significant association between sleep duration and weight gain or obesity was found for women.

Conclusions:

Short sleep duration was associated with weight gain and the development of obesity over 1 year in men, but not in women.

Citation:

Watanabe M; Kikuchi H; Tanaka T; Takahashi M. Association of short sleep duration with weight gain and obesity at 1-year follow-up: a large-scale prospective study. SLEEP 2010;33(2):161-167.     

Insomnia with Short Sleep Duration and Mortality: The Penn State Cohort

Study Objectives:

Because insomnia with objective short sleep duration is associated with increased morbidity, we examined the effects of this insomnia subtype on all-cause mortality.

Design:

Longitudinal.

Setting:

Sleep laboratory.

Participants:

1,741 men and women randomly selected from Central Pennsylvania.

Measurements:

Participants were studied in the sleep laboratory and were followed-up for 14 years (men) and 10 years (women). “Insomnia” was defined by a complaint of insomnia with duration ≥ 1 year. “Normal sleeping” was defined as absence of insomnia. Polysomnographic sleep duration was classified into two categories: the “normal sleep duration group” subjects who slept ≥ 6 h and the “short sleep duration group” subjects who slept < 6 h. We adjusted for age, race, education, body mass index, smoking, alcohol, depression, sleep disordered breathing, and sampling weight.

Results:

The mortality rate was 21% for men and 5% for women. In men, mortality risk was significantly increased in insomniacs who slept less than 6 hours compared to the “normal sleep duration, no insomnia” group, (OR = 4.00, CI 1.14-13.99) after adjusting for diabetes, hypertension, and other confounders. Furthermore, there was a marginally significant trend (P = 0.15) towards higher mortality risk from insomnia and short sleep in patients with diabetes or hypertension (OR = 7.17, 95% CI 1.41-36.62) than in those without these comorbid conditions (OR = 1.45, 95% CI 0.13-16.14). In women, mortality was not associated with insomnia and short sleep duration.

Conclusions:

Insomnia with objective short sleep duration in men is associated with increased mortality, a risk that has been underestimated.

Citation:

Vgontzas AN; Liao D; Pejovic S; Calhoun S; Karataraki M; Basta M; Fernández-Mendoza J; Bixler EO. Insomnia with short sleep duration and mortality: the Penn State Cohort. SLEEP 2010;33(9):1159-1164.     

Associations of Sleep Duration and Screen Time with Incidence of Overweight in European Children: The IDEFICS/I.Family Cohort

IntroductionOver the past decades, children have been increasingly using screen devices, while at the same time their sleep duration has decreased. Both behaviors have been associated with excess weight, and it is possible they act as mutually reinforcing behaviors for weight gain. The aim of the study was to explore independent, prospective associations of screen time and sleep duration with incident overweight in a sample of European children.MethodsData from 4,285 children of the IDEFICS/I.Family cohort who were followed up from 2009/2010 to 2013/2014 were analyzed. Hours per day of screen time and of sleep duration were reported by parents at baseline. Logistic regression analyses were carried out in separate and mutually adjusted models controlled for sex, age, European country region, parental level of education, and baseline BMI z-scores.ResultsAmong normal weight children at baseline (N = 3,734), separate models suggest that every hour increase in screen time and every hour decrease in sleep duration were associated with higher odds of the child becoming overweight or obese at follow-up (OR = 1.16, 95% CI: 1.02–1.32 and OR = 1.23, 95% CI: 1.05–1.43, respectively). In the mutually adjusted model, both associations were attenuated slightly (screen time OR = 1.13, 95% CI: 0.99–1.28; sleep duration OR = 1.20, 95% CI: 1.03–1.40), being consistently somewhat stronger for sleep duration.Discussion/ConclusionBoth screen time and sleep duration increased the incidence of overweight or obesity by 13–20%. Interventions that include an emphasis on adequate sleep and minimal screen time are needed to establish their causal role in the prevention of overweight and obesity among European children.     

The Effect of Short Sleep Duration on Coronary Heart Disease Risk is Greatest Among Those with Sleep Disturbance: A Prospective Study from the Whitehall II Cohort

Study Objectives:

Short sleep duration is associated with increased CHD (coronary heart disease) mortality and morbidity, although some evidence suggests that sleep disturbance is just as important. We investigated whether a combination of short sleep duration and sleep disturbance is associated with a higher risk of CHD than their additive effects.

Setting:

The Whitehall II study.

Patients or Participants:

The Whitehall II study recruited 10,308 participants from 20 civil service departments in London, England. Participants were between the ages of 35 and 55 years at baseline (1985-1988) and were followed up for an average of 15 years.

Interventions:

N/A.

Measurements:

Sleep hours and sleep disturbance (from the General Heath Questionnaire-30) were obtained from the baseline survey. CHD events included fatal CHD deaths or incident nonfatal myocardial infarction or angina (ICD-9 codes 410-414 or ICD-10 I20-25).

Results:

Short sleep duration and sleep disturbance were both associated with increased hazards for CHD in women as well as in men, although, after we adjusted for confounders, only those reporting sleep disturbance had a raised risk. There was some evidence for an interaction between sleep duration and sleep disturbance. Participants with short sleep duration and restless disturbed nights had the highest hazard ratios (HR) of CHD (relative risk:1.55, 95% confidence interval:1.33-1.81). Among participants who did not report any sleep disturbance, there was little evidence that short sleep hours increased CHD risk.

Conclusion:

The effect of short sleep (≤ 6 hours) on increasing CHD risk is greatest among those who reported some sleep disturbance. However, among participants who did not report any sleep disturbance, there was little evidence that short sleep hours increased CHD risk.

Citation:

Chandola T; Ferrie JE; Perski A; Akbaraly T; Marmot MG. The effect of short sleep duration on coronary heart disease risk is greatest among those with sleep disturbance: a prospective study from the Whitehall II cohort. SLEEP 2010;33(6):739-744     

Stress and weight change in university students in the United Kingdom

Students in the US have been shown to gain weight during their first year at university. This study examined whether students in Britain have a similar weight change during their first year at university, and tested the hypothesis that stress plays a role. A cross-sectional survey was conducted to assess stress and perceived weight change. Two hundred and sixty eight students at University College London completed the questionnaire at the end of their first year of university. On average, students reported a significant weight increase (1.53 kg+/-2.70, p<0.001), although there was considerable variation, with 55% of the sample reporting weight gain, 12% weight loss, and 33% remaining stable. Logistic regression analyses demonstrated that stress was associated with greater risk of weight gain (OR, 1.27, 95% CI, 1.12 to 1.44, p=0.001) and weight loss (1.33, 1.10 to 1.61, p=0.003), but associations were stronger among women. The associations remained unchanged after adjustment for health behaviours. Our findings confirm a modest weight gain over the first year at university, which was associated with higher levels of perceived stress in women.     

The association between sleep duration and weight gain in adults: a 6-year prospective study from the Quebec Family Study

STUDY OBJECTIVE: To investigate the relationship between sleep duration and subsequent body weight and fat gain. DESIGN: Six-year longitudinal study. SETTING: Community setting. PARTICIPANTS: Two hundred seventy-six adults aged 21 to 64 years from the Quebec Family Study. More than half of the sample is drawn from families with at least 1 parent and 1 offspring with a body mass index of 32 kg/m2 or higher. MEASUREMENTS AND RESULTS: Body composition measurements and self-reported sleep duration were determined. Changes in adiposity indices were compared between short- (5-6 hours), average- (7-8 hours), and long- (9-10 hours) duration sleeper groups. After adjustment for age, sex, and baseline body mass index, short-duration sleepers gained 1.98 kg (95% confidence interval: 1.16-2.82) more and long-duration sleepers gained 1.58 kg (95% CI: 1.02-2.56) more than did average-duration sleepers over 6 years. Short- and long-duration sleepers were 35% and 25% more likely to experience a 5-kg weight gain, respectively, as compared with average-duration sleepers over 6 years. The risk of developing obesity was elevated for short- and long-duration sleepers as compared with average-duration sleepers, with 27% and 21% increases in risk, respectively. These associations remained significant after inclusion of important covariates and were not affected by adjustment for energy intake and physical activity participation. CONCLUSIONS: This study provides evidence that both short and long sleeping times predict an increased risk of future body weight and fat gain in adults. Hence, these results emphasize the need to add sleep duration to the panel of determinants that contribute to weight gain and obesity.     

Association between short sleep and suicidal ideation and suicide attempt among adults in the general population

OBJECTIVE: To determine the association between sleep, mental disorders, and suicidal ideation (SI) and suicide attempt (SA) among adults in the community. DESIGN: Cross-sectional. SETTING: National Comorbidity Survey (n = 8098). PARTICIPANTS: A representative sample of adults in the United States. MEASUREMENTS AND RESULTS: Multiple logistic regression analyses were used to determine the association between usual number of hours of sleep during a 24-h period and SI and SA (past 12 months and lifetime). Analyses were adjusted for differences in demographic characteristics and comorbid mental disorders. Additional analyses examined the relationship between hours of sleep and the odds of SA among adults with SI, compared with SI without SA. Short sleep was associated with significantly increased odds of SI (OR 2.5, 95% CI: 1.6-3.9) and SA (OR 3.0, 95% CI: 1.4-6.4), and with SA among those with SI (past 12 months). These associations persisted after adjusting for differences in demographic characteristics and mental disorders, though the links between short sleep and SA among those with SI were no longer statistically significant after adjusting for panic, mood, and substance use disorders. CONCLUSIONS: Short sleep appears to be associated with increased likelihood of SI and SA, independent of the effects of comorbid mental disorders, among adults in the community. Among adults with SI, short sleep is associated with increased odds of SA, and this association seems largely related to the presence of panic attacks, mood, and substance use disorders. Future studies should investigate the nature of these relationships, and whether and how mental health problems may play a role.     

Bidirectional associations of sleep and discretionary screen time in adults: Longitudinal analysis of the UK biobank

The direction of the association between discretionary screen time (DST) and sleep in the adult population is largely unknown. We examined the bidirectional associations of DST and sleep patterns in a longitudinal sample of adults in the general population. A total of 31,361 UK Biobank study participants (52% female, 56.1 ± 7.5 years) had two repeated measurements of discretionary screen time (TV viewing and leisure-time computer use) and self-reported sleep patterns (five sleep health characteristics) between 2012 and 2018 (follow-up period of 6.9 ± 2.2 years). We categorised daily DST into three groups (low, <3 h/day; medium, 3–4 h/day; and high, >4 h/day), and calculated a sleep pattern composite score comprising morning chronotype, adequate sleep duration (7–8 h/day), never or rare insomnia, never or rare snoring, and infrequent daytime sleepiness. The overall sleep pattern was categorised into three groups (healthy: ≥ 4; intermediate: 2–3; and poor: ≤ 1 healthy sleep characteristic). Multiple logistic regression analyses were applied to assess associations between DST and sleep with adjustments for potential confounders. Participants with either an intermediate (OR: 1.40; 95% CI: 1.15, 1.71) or a poor (OR: 1.16; 95% CI: 1.10, 1.24) sleep pattern at baseline showed higher odds for high DST at follow-up, compared with those with a healthy baseline sleep pattern. Participants with medium (OR: 1.40; 95% CI: 1.14, 1.71) or high DST (OR: 1.62; 95% CI: 1.30, 2.00) at baseline showed higher odds for poor sleep at follow-up, compared with participants with a low DST. In conclusion, our findings provide consistent evidence that a high DST at baseline is associated with poor sleep over a nearly 7 year follow-up period, and vice versa.     

The Association between Sleep Duration and Non-Alcoholic Fatty Liver Disease among Japanese Men and Women

ObjectiveTo examine the relationship between sleep duration and non-alcoholic fatty liver disease (NAFLD).MethodsWe evaluated 3,968 subjects who underwent health check-ups from June 2012 to May 2013 at the Watari Hospital Health Center in Fukushima Prefecture in Japan. Fatty liver was detected by ultrasonography. Sleep duration and lifestyle factors were estimated using a questionnaire. Sleep duration was categorized into the following groups: ≤6, 6 to ≤7, >7 to ≤8, and >8 h. The four sleep duration groups were compared using the χ² test and Kruskal-Wallis test.ResultsIn total, 2,172 subjects were enrolled. The overall prevalence of NAFLD was 29.6% (men, 38.0%; women, 25.3%). The proportion of NAFLD tended to decrease as sleep duration increased in men. The proportion with NAFLD was lowest in the group with a sleep duration of 6 to ≤7 h and highest in the groups with sleep durations of ≤6 and >8 h in women. The distribution showed a U-shaped curve. The age-adjusted odds ratio (OR) (95% confidence interval (CI)) for subjects with NAFLD with a sleep duration ≤6 h compared to the reference (6 to ≤7 h) was 1.44 (1.06-1.96) in women.ConclusionSleep shortage tends to be associated with NAFLD in women and may be mediated by body adiposity.Key Words: NAFLD, s; Short sleep duration; U-shaped curve; Women     

Fibrinogen may mediate the association between long sleep duration and coronary heart disease

Long sleep duration has been associated with increased risk of cardiovascular disease (CVD) and all‐cause mortality. Inflammation and coagulation have been hypothesized as possible physiological pathways to explain this association, although specific biomarkers have not been studied. Using longitudinal data from 3942 postmenopausal women in the Women's Health Initiative observational study and clinical trials, we investigated whether fibrinogen, an acute‐phase inflammatory protein involved in blood clotting, mediates the associations between sleep duration and coronary heart disease (CHD) and mortality among women. Fibrinogen levels were associated positively with self‐reported long sleep duration (9+ h per night), CHD and all‐cause mortality, even after adjustment for a range of sociodemographic characteristics, cardiovascular risk factors and comorbidities.Compared with self‐reported 7–8 h per night sleep duration, self‐reported long sleep duration was associated with increased odds of CHD [odds ratio (OR) = 2.05, 95% confidence interval (CI): 1.02–4.11]. Adjustment for fibrinogen levels reduced the increased odds of CHD associated with long sleep by approximately 8 percentage points (OR = 1.97, 95% CI: 0.98–3.97). A similar reduction in the OR was observed with mortality. For both outcomes there is support for partial mediation of 6–7%, suggesting that fibrinogen may be a mechanism through which long sleep duration is associated with CHD and mortality.     

Association between sleep duration and high blood pressure in adolescents: a systematic review and meta-analysis

Context: Sleep has been assessed as a risk factor for health consequences. Among adults, excessively longer and shorter sleep durations are associated with high blood pressure (BP), but knowledge of the association between sleep duration and high BP among adolescents is limited.

Objectives: To estimate the associations between sleep duration and high BP in adolescents.

Methods: PubMed, Web of Science, and Cochrane databases were searched for eligible publications up until 20 November 2017. This study reviewed the reference lists from retrieved articles to search for relevant studies. Pooled odds ratios (ORs) were calculated using a random-effects meta-analysis. Sub-group and sensitivity analyses were conducted to identify heterogeneity. Publication bias was evaluated using Egger’s test.

Results: Seven studies involving 21,150 participants were included, with ages ranging from 10–18 years. For primary analysis, compared with the reference sleep duration, the pooled OR for high BP was 1.51 (95% confidence interval [CI]?=?1.04–2.19) for the short sleep duration overall. For long sleep duration, the pooled OR was 1.04 (95% CI?=?0.78–1.38). Further sub-group analysis showed that short sleep duration had a higher risk of incident high BP in males (OR?=?1.55, 95% CI?=?1.24–1.93) than in females (OR?=?1.23, 95% CI?=?0.47–3.22).

Conclusions: Among adolescents, and particularly male adolescents, short sleep duration may be a risk factor for high BP. More attention should be given to this lifestyle factor.     

Mortality risk factors in sleep apnoea: a matched case-control study

Sleep apnoea syndrome was reported to be associated with increased mortality but it is not known if this association is independent of obesity and co-morbidities. The present study investigated predictors of mortality in a large cohort of men with sleep apnoea using a case-control design. The study population consisted of 10,981 men diagnosed during 1991-2000 by whole-night polysomnography with sleep apnoea; 331 men died prior to 1 September 2001, of whom 277 were matched by age, gender, site and time of study to patients who were alive in September 2001. Multivariate analysis revealed that all-cause mortality was associated with chronic obstructive pulmonary disease (COPD) (odds ratio, OR: 7.07, 95% CI 2.75-18.16), chronic heart failure (CHF) (OR: 5.47, 95% CI 1.06-28.31), diabetes mellitus (DM) (OR: 3.30, 95% CI 1.51-7.20) and body mass index (BMI) (increase of 5 kg m(-2), OR: 1.44, 95% CI: 1.04-1.99). Chronic upper airway problems were associated with survival (OR: 0.45, 95% CI 0.23-0.90). There were significant interactions between respiratory disturbance index and BMI and COPD. Mortality of patients younger than the median age (62 years) was associated with COPD, DM and an interaction between BMI and apnoea severity. Predictors of mortality for the older patients were COPD, CHF and DM. We conclude that all-cause mortality in sleep apnoea is associated with co-morbidities and obesity. Severity of sleep apnoea affects mortality by interacting with obesity and lung disease.     

Sleep Duration and Glycemic Control in Patients with Diabetes Mellitus: Korea National Health and Nutrition Examination Survey 2007-2010

Short sleep duration has been reported to increase the risk of diabetes. However, the influence of sleep duration on glycemic control in diabetic patients has not been clarified. In this study we evaluated the association between sleep duration and glycemic control in diabetic patients. We analyzed the data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2007-2010. Sleep duration was classified into five groups: <6, 6, 7, 8, and ≥9 h/day. Fasting blood glucose and HbA1c showed a U-shaped trend according to sleep duration. Sleep duration of 7 h/day had the lowest HbA1c (7.26%) among the subjects (P=0.026). In the older age group (≥65 yr), a sleep duration of 6 h/day was associated with the lowest HbA1c (7.26%). The adjusted odds ratio (OR) with a 95% confidence interval (CI) of worse glycemic control (HbA1c ≥7.0%) in group of sleep duration of ≥9 h/day was 1.48 (1.04-2.13) compared with the group of 7 h/day. This relationship disappeared after adjusting duration of diabetes (OR, 1.38; 95% CI, 0.93-2.03). Our results suggest that sleep duration and glycemic control in diabetic patients has U-shaped relationship which was mainly affected by duration of diabetes.     

Bidirectional associations between insomnia symptoms and unhealthy behaviours

It has been suggested that there are associations among insomnia symptoms and unhealthy behaviours. However, previous studies are sparse and mainly cross‐sectional, and have not been focused on several key unhealthy behaviours. The aim of this study was to examine whether the associations are bidirectional, i.e. whether insomnia symptoms are associated with subsequent unhealthy behaviours, and whether unhealthy behaviours are associated with subsequent insomnia symptoms. The data were derived from the Helsinki Health Study prospective cohort study. The baseline data were collected in 2000–02 (n = 8960, response rate 67%) among 40–60‐year‐old employees of the City Helsinki, Finland. The follow‐up data were collected in 2007 (n = 7332, response rate 83%). Logistic regression analysis was used to examine the associations among insomnia symptoms and unhealthy behaviours, including smoking, heavy and binge drinking, physical inactivity and unhealthy food habits. Frequent insomnia symptoms at baseline were associated with subsequent heavy drinking [odds ratio (OR): 1.34; 95% confidence interval (CI): 1.07–1.68] and physical inactivity (OR: 1.27; 95% CI: 1.08–1.48) after full adjustment for gender, age, corresponding unhealthy behaviour at baseline, marital status, occupational class, sleep duration and common mental disorders. Additionally, heavy drinking (OR: 1.48; 95% CI: 1.22–1.80) and binge drinking (OR: 1.26; 95% CI: 1.08–1.46) at baseline were associated with subsequent insomnia symptoms at follow‐up after full adjustment. In conclusion, insomnia symptoms were associated with subsequent heavy drinking and physical inactivity, and heavy and binge drinking were also associated with subsequent insomnia symptoms.     

Associations of usual sleep duration with serum lipid and lipoprotein levels

STUDY OBJECTIVES: We examined the individual association between sleep duration and a high serum triglyceride, low HDL cholesterol, or high LDL cholesterol level. DESIGN AND SETTING: The present study analyzed data from the National Health and Nutrition Survey that was conducted in November 2003 by the Japanese Ministry of Health, Labour and Welfare. This survey was conducted on residents in the districts selected randomly from all over Japan. PARTICIPANTS: The subjects included in the statistical analysis were 1,666 men and 2,329 women aged 20 years or older. INTERVENTION: N/A. MEASUREMENTS AND RESULTS: Among women, both short and long sleep durations are associated with a high serum triglyceride level or a low HDL cholesterol level. Compared with women sleeping 6 to 7 h, the relative risk of a high triglyceride level among women sleeping <5 h was 1.51 (95% CI, 0.96-2.35), and among women sleeping > or =8 h was 1.45 (95% CI, 1.00-2.11); the relative risk of a low HDL cholesterol level among women sleeping <5 h was 5.85 (95% CI, 2.29-14.94), and among women sleeping > or =8 h was 4.27 (95% CI, 1.88-9.72). On the other hand, it was observed that the risk of a high LDL cholesterol level was lower among men sleeping > or =8 h. These analyses were adjusted for the following items: age, blood pressure, body mass index, plasma glucose level, smoking habit, alcohol consumption, dietary habits, psychological stress, and taking cholesterol-lowering medications. CONCLUSIONS: Usual sleep duration is closely associated with serum lipid and lipoprotein levels.