Self-reported and tracked nighttime smartphone use and their association with overweight and cardiometabolic risk markers.

Nighttime smartphone use is associated with sleep problems, which in turn have a bidirectional association with overweight. We aim to investigate whether nighttime smartphone use and sleep are related to overweight and metabolic dysfunction in adult populations. We used data from three population samples (aged 16-89) from the SmartSleep Study, which included survey data (N = 29,838), high-resolution tracking data (N = 3446), follow-up data (N = 1768), and cardiometabolic risk markers (N = 242). Frequent self-reported nighttime smartphone use was associated with 51% higher odds (95% CI: 1.32; 1.70) of overweight compared with no use. Tracked nighttime smartphone use was also associated with overweight. Similar results were found for obesity as an outcome. No consistent associations were found between nighttime smartphone use and cardiometabolic risk markers in a small subsample of healthy young women. Poor sleep quality (vs. good sleep quality) was associated with overweight (OR = 1.19, 85% CI: 1.10; 1.28). Overall, frequent nighttime smartphone use was consistently associated with overweight and a higher BMI across diverse population samples. The bidirectional interplay between nighttime smartphone use, sleep, and overweight may create a vicious circle of metabolic dysfunction over time. Therefore, nighttime smartphone use may be a potential target point for public health interventions to reduce overweight at the population level.

Cohort profile: The SmartSleep Study, Denmark, combining evidence from survey, clinical and tracking data.

PURPOSE: The SmartSleep Study is established to comprehensively assess the impact of night-time smartphone use on sleep patterns and health. An innovative combination of large-scale repeated survey information, high-resolution sensor-driven smartphone data, in-depth clinical examination and registry linkage allows for detailed investigations into multisystem physiological dysregulation and long-term health consequences associated with night-time smartphone use and sleep impairment. PARTICIPANTS: The SmartSleep Study consists of three interconnected data samples, which combined include 30 673 individuals with information on smartphone use, sleep and health. Subsamples of the study population also include high-resolution tracking data (n=5927) collected via a customised app and deep clinical phenotypical data (n=245). A total of 7208 participants are followed in nationwide health registries with full data coverage and long-term follow-up. FINDINGS TO DATE: We highlight previous findings on the relation between smartphone use and sleep in the SmartSleep Study, and we evaluate the interventional potential of the citizen science approach used in one of the data samples. We also present new results from an analysis in which we use 803 000 data points from the high-resolution tracking data to identify clusters of temporal trajectories of night-time smartphone use that characterise distinct use patterns. Based on these objective tracking data, we characterise four clusters of night-time smartphone use. FUTURE PLANS: The unprecedented size and coverage of the SmartSleep Study allow for a comprehensive documentation of smartphone activity during the entire sleep span. The study has been expanded by linkage to nationwide registers, which allow for further investigations into the long-term health and social consequences of night-time smartphone use. We also plan new rounds of data collection in the coming years.

Burden of Medication Overuse in Migraine: A Cross-sectional, Population-Based Study in Five European Countries Using the 2020 National Health and Wellness Survey (NHWS).

INTRODUCTION: Overuse of medication to treat migraine attacks can lead to development of a new type of headache or significant worsening of pre-existing headache, known as medication overuse headache. However, data concerning the burden of medication overuse (MO) in migraine are limited. This study aimed to assess the humanistic burden of MO in individuals with migraine from five European countries. METHODS: Data are from the 2020 National Health and Wellness Survey-a cross-sectional, population-based survey conducted in France, Germany, Italy, Spain, and the UK. Data were included from adults (≥ 18 years) with a self-reported diagnosis of migraine and at least one migraine attack and one headache in the past 30 days. MO was defined as (i) use of simple analgesics/over-the-counter medications on ≥ 15 days/month; or (ii) use of migraine medication, including combination analgesics, on ≥ 10 days/month. Humanistic burden of MO was assessed using the 12-Item Short-Form Health Survey (SF-12v2), EuroQol 5-Dimensions 5-Levels (EQ-5D), Short-Form 6-Dimensions (SF-6D), and Migraine Disability Assessment (MIDAS). The association of MO with humanistic burden was evaluated using generalized linear models adjusted for potential confounders in the full migraine population and in subgroups defined by headache frequency (monthly headache days [MHDs] 1-3, 4-7, 8-14, or ≥ 15). RESULTS: Among individuals with migraine, humanistic burden (SF-12v2, SF-6D, EQ-5D, and MIDAS) was higher in individuals who reported MO (n = 431) versus no MO (n = 3554), even after adjustment for confounding variables (p < 0.001 for all measures). MIDAS and EQ-5D scores were higher in individuals with MO than without, at all levels of headache frequency. For SF-12v2 and SF-6D, differences between groups with/without MO were seen only at lower levels of headache frequency (MHD 1-3 and 4-7). CONCLUSION: Among people with migraine, those who report MO face a greater humanistic burden than those without MO, irrespective of headache frequency.

Night-time smartphone use, sleep duration, sleep quality, and menstrual disturbances in young adult women: A population-based study with high-resolution tracking data.

Study Objectives: To explore the relationship among night-time smartphone use, sleep duration, sleep quality, and menstrual disturbances in young adult women. Methods: Women aged 18-40 years were included in the SmartSleep Study in which they objectively tracked their smartphone use via the SmartSleep app between self-reported sleep onset and offset times (n = 764) and responded to a survey (n = 1068), which included background characteristics, sleep duration, sleep quality (Karolinska Sleep Questionnaire), and menstrual characteristics (International Federation of Gynecology and Obstetrics' definitions). Results: The median tracking time was four nights (interquartile range: 2-8). Higher frequency (p = .05) and longer duration (p = .02) of night-time smartphone use were associated with long sleep duration (≥9 h), but not with poor sleep quality or short sleep duration (<7 h). Short sleep duration was associated with menstrual disturbances (OR = 1.84, 95% confidence interval [CI] = 1.09 to 3.04) and irregular menstruation (OR = 2.17, 95% CI = 1.08 to 4.10), and poor sleep quality was associated with menstrual disturbances (OR = 1.43, 95% CI = 1.19 to 1.71), irregular menstruation (OR = 1.34, 95% CI = 1.04 to 1.72), prolonged bleedings (OR = 2.50, 95% CI = 1.44 to 4.43) and short-cycle duration (OR = 1.40, 95% CI = 1.06 to 1.84). Neither duration nor frequency of night-time smartphone use was associated with menstrual disturbances. Conclusions: Night-time smartphone use was associated with longer sleep duration, but not with menstrual disturbances in adult women. Short sleep duration and sleep quality were associated with menstrual disturbances. Further investigation of the effects of night-time smartphone use on sleep and female reproductive function in large prospective studies is needed.

Nighttime smartphone use and changes in mental health and wellbeing among young adults: a longitudinal study based on high-resolution tracking data.

Frequent nighttime smartphone use can disturb healthy sleep patterns and may adversely affect mental health and wellbeing. This study aims at investigating whether nighttime smartphone use increases the risk of poor mental health, i.e. loneliness, depressive symptoms, perceived stress, and low life satisfaction among young adults. High-dimensional tracking data from the Copenhagen Network Study was used to objectively measure nighttime smartphone activity. We recorded more than 250,000 smartphone activities during self-reported sleep periods among 815 young adults (university students, mean age: 21.6 years, males: 77%) over 16 weekdays period. Mental health was measured at baseline using validated measures, and again at follow-up four months later. Associations between nighttime smartphone use and mental health were evaluated at baseline and at follow-up using multiple linear regression adjusting for potential confounding. Nighttime smartphone use was associated with a slightly higher level of perceived stress and depressive symptoms at baseline. For example, participants having 1-3 nights with smartphone use (out of 16 observed nights) had on average a 0.25 higher score (95%CI:0.08;0.41) on the Perceived stress scale ranging from 0 to 10. These differences were small and could not be replicated at follow-up. Contrary to the prevailing hypothesis, nighttime smartphone use is not strongly related to poor mental health, potentially because smartphone use is also a social phenomenon with associated benefits for mental health.

Predicting stress and depressive symptoms using high-resolution smartphone data and sleep behavior in Danish adults.

STUDY OBJECTIVES: The early detection of mental disorders is crucial. Patterns of smartphone behavior have been suggested to predict mental disorders. The aim of this study was to develop and compare prediction models using a novel combination of smartphone and sleep behavior to predict early indicators of mental health problems, specifically high perceived stress and depressive symptoms. METHODS: The data material included two separate population samples nested within the SmartSleep Study. Prediction models were trained using information from 4522 Danish adults and tested in an independent test set comprising of 1885 adults. The prediction models utilized comprehensive information on subjective smartphone behavior, objective night-time smartphone behavior, and self-reported sleep behavior. Receiver operating characteristics area-under-the-curve (ROC AUC) values obtained in the test set were recorded as the performance metrics for each prediction model. RESULTS: Neither subjective nor objective smartphone behavior was found to add additional predictive information compared to basic sociodemographic factors when forecasting perceived stress or depressive symptoms. Instead, the best performance for predicting poor mental health was found in the sleep prediction model (AUC = 0.75, 95% CI: 0.72-0.78) for perceived stress and (AUC = 0.83, 95%CI: 0.80-0.85) for depressive symptoms, which included self-reported information on sleep quantity, sleep quality and the use of sleep medication. CONCLUSIONS: Sleep behavior is an important predictor when forecasting mental health symptoms and it outperforms novel approaches using objective and subjective smartphone behavior.

The SmartSleep Experiment: Evaluation of changes in night-time smartphone behavior following a mass media citizen science campaign.

The increasing 24-hour smartphone use is of public health concern. This study aims to evaluate whether a massive public focus on sleep and smartphone use generated through a large-scale citizen science project, the SmartSleep Experiment, influence participants' night-time smartphone behavior. A total of 8,894 Danish adults aged 16 and above participated in the SmartSleep Experiment, a web-based survey on smartphones and sleep behavior. The survey was carried out for one week in 2018, combined with an extensive national mass media campaign focusing on smartphone behaviors and sleep. A follow-up survey aimed at evaluating whether survey-participants had changed their night-time smartphone behavior was carried out two weeks after the campaign. A total of 15% of the participants who used their smartphone during sleep hours at baseline had changed their night-time smartphone behavior, and 83% of those indicated that they used their smartphone less at follow-up. The participants who had changed their smartphone behavior had primarily taken active precautions to avoid night-time smartphone use, e.g., activating silent mode (36%) or reduced their smartphone use before (50%) and during sleep hours (52%). The reduction in sleep problems (54%), recognition of poor smartphone behavior (48%), and the increased focus on night-time smartphone use (42%) were motivational factors for these behavior changes. Using citizen science and mass media appeared to be associated with changes in night-time smartphone behavior. Public health projects may benefit from combining citizen science with other interventional approaches.

Loneliness, worries, anxiety, and precautionary behaviours in response to the COVID-19 pandemic: A longitudinal analysis of 200,000 Western and Northern Europeans.

BACKGROUND: In response to the COVID-19 pandemic, governments around the world instituted various public-health measures. Our project aimed to highlight the most significant similarities and differences in key mental-health indicators between four Western and Northern European countries, and identify the population subgroups with the poorest mental-health outcomes during the first months of the pandemic. METHODS: We analysed time-series survey data of 205,084 individuals from seven studies from Denmark, France, the Netherlands, and the UK to assess the impact of the pandemic and associated lockdowns. All analyses focused on the initial lockdown phase (March-July 2020). The main outcomes were loneliness, anxiety, and COVID-19-related worries and precautionary behaviours. FINDINGS: COVID-19-related worries were consistently high in each country but decreased during the gradual reopening phases. While only 7% of the respondents reported high levels of loneliness in the Netherlands, percentages were higher in the rest of the three countries (13-18%). In all four countries, younger individuals and individuals with a history of mental illness expressed the highest levels of loneliness. INTERPRETATION: The pandemic and associated country lockdowns had a major impact on the mental health of populations, and certain subgroups should be closely followed to prevent negative long-term consequences. Younger individuals and individuals with a history of mental illness would benefit from tailored public-health interventions to prevent or counteract the negative effects of the pandemic. Individuals across Western and Northern Europe have thus far responded in psychologically similar ways despite differences in government approaches to the pandemic. FUNDING: See the Funding section.

Daytime and nighttime smartphone use: A study of associations between multidimensional smartphone behaviours and sleep among 24,856 Danish adults.

The around-the-clock smartphone use and its relation to disturbed sleep is a public health concern. The present study aimed to quantify the effects of different dimensions of smartphone behaviours (frequency of daytime use, problematic use, use before sleep and use during the sleep period) on disturbed sleep (sleep quality and sleep quantity) and to disentangle their inter-relationship in a large population-based sample of 24,856 Danish adults aged ≥16 years. Data come from the SmartSleep Experiment, which is a web-based survey carried out using a citizen science approach. Tested items were used to evaluate smartphone use and disturbed sleep was evaluated with the Karolinska Sleep Questionnaire (KSQ). Linear and multinomial logistic regression was employed to evaluate the relationship between smartphone use and disturbed sleep. While several of the smartphone measures were associated with disturbed sleep when assessed individually, smartphone use during the sleep period was the only dimension consistently associated with disturbed sleep when assessed independently of other smartphone behaviours. Weekly smartphone use during the sleep period versus no use was associated on average with a 0.96 point higher score (95% confidence interval [CI] 0.90-1.02) on the 5-point KSQ scale, and a higher risk of both short (odds ratio [OR] 1.32, 95% CI 1.08-1.62) and long (OR 1.94, 95% CI 1.63-2.32) sleep duration. Smartphone use during the sleep period is the factor strongest associated to disturbed sleep relative to other dimensions of smartphone use. Recommendations around smartphone use during the sleep period are warranted in order to protect the fundamentally important biological and mental processes of sleep.

Smartphone interactions and mental well-being in young adults: A longitudinal study based on objective high-resolution smartphone data.

Aims: To investigate the effects of objectively measured smartphone interactions on indicators of mental well-being among men and women in a population of young adults. Methods: A total of 816 young adults (mean±SD age 21.6±2.6 years; 77% men) from the Copenhagen Network Study were followed with objective recordings of smartphone interactions from calls, texts and social media. Participants self-reported on loneliness, depressive symptoms and disturbed sleep at baseline and in a four-month (interquartile range 75-163 days) follow-up survey. Multiple linear regression was used to analyse the association between smartphone interactions and mental well-being separately for men and women. Results: A higher number of smartphone interactions was associated with lower levels of loneliness at baseline and the same pattern appeared for depressive symptoms, although this was less pronounced. A high level of smartphone interaction was associated with lower levels of disturbed sleep for men, but not for women. In follow-up analyses, a high versus low level of smartphone interaction was associated with an increase in loneliness and depressive symptoms over time for women, but not for men. Conclusions: Smartphone interactions are related to better mental well-being, which may be attributed to the beneficial effects of an underlying social network. Over time, accommodating a large network via smartphone communication might, however, have negative effects on mental well-being for women.

'Standing together - at a distance': Documenting changes in mental-health indicators in Denmark during the COVID-19 pandemic.

Aims: There is a need to document the mental-health effects of the COVID-19 pandemic and its associated societal lockdowns. We initiated a large mixed-methods data collection, focusing on crisis-specific worries and mental-health indicators during the lockdown in Denmark. Methods: The study incorporated five data sources, including quantitative surveys and qualitative interviews. The surveys included a time series of cross-sectional online questionnaires starting on 20 March 2020, in which 300 (3×100) Danish residents were drawn every three days from three population groups: the general population (N=1046), families with children (N=1032) and older people (N=1059). These data were analysed by trend analysis. Semi-structured interviews were conducted with 32 people aged 24-83 throughout Denmark to provide context to the survey results and to gain insight into people's experiences of the lockdown. Results: Absolute level of worries, quality of life and social isolation were relatively stable across all population groups during the lockdown, although there was a slight deterioration in older people's overall mental health. Many respondents were worried about their loved ones' health (74-76%) and the potential long-term economic consequences of the pandemic (61-66%). The qualitative interviews documented significant variation in people's experiences, suggesting that the lockdown's effect on everyday life had not been altogether negative. Conclusions: People in Denmark seem to have managed the lockdown without alarming changes in their mental health. However, it is important to continue investigating the effects of the pandemic and various public-health measures on mental health over time and across national contexts.

High perceived stress and social interaction behaviour among young adults. A study based on objective measures of face-to-face and smartphone interactions.

Stress and mental health problems impede social functioning and may also complicate relationship formation with peers. The aim was to investigate whether high perceived stress among young adults is associated with social interaction behaviour both via face-to-face interaction and via smartphone interaction. The data was derived from the Copenhagen Network Study, where 535 first-year students (mean age 21.3, 77% male) self-reported on perceived stress at baseline and were subsequently followed for three months with continuous Bluetooth recordings of face-to-face interactions and smartphone interactions (calls and texts) measuring the network size, frequency, and duration of interactions. Logistic regression was used to assess associations between perceived stress (high/low) and social interactions adjusting for sex, age, and personality traits. Participants with high perceived stress were more likely to engage in a larger call and text network and have a higher call and text frequency compared to individuals with low perceived stress. We found a non-statistically significant tendency that participants with a high perceived stress level spend less time meeting face to face with peers. Stressed students engage in frequent smartphone interaction which may be explained by a social support seeking behaviour, or it may be that accommodating a large network via the smartphone is stress-inducing.

Overnight smartphone use: A new public health challenge? A novel study design based on high-resolution smartphone data.

BACKGROUND: Round-the-clock use of smartphones holds a potential for awakenings and/or shorter sleep duration, which may have adverse health consequences. We aim to describe overnight smartphone activity among young adults and to characterize those with smartphone interrupted sleep in terms of sleep impairment and mental and physical health indicators. METHODS: We use unique objective high-resolution information on timing of smartphone activity (based on >250,000 phone actions) continuously monitored over a four-week period among 815 young adults combined with indicators of mental and physical health. RESULTS: We find substantial overnight smartphone activity. More than 12% had smartphone activity in the middle of the night (3 to 5 hours after self-reported bedtime) and 41% had smartphone interrupted sleep on at least one weekday during a 4-week period. Those with frequent smartphone interrupted sleep had on average 48 minutes shorter self-reported sleep duration and higher body mass index, whereas there were no differences in physical or mental health symptoms. CONCLUSIONS: The substantial smartphone activity during bed hours among young adults may pose a public health challenge and especially the relation to overweight warrants close attention.

Measuring social integration and tie strength with smartphone and survey data.

Recordings of smartphone use for contacts are increasingly being used as alternative or supplementary measurement methods for social interactions and social relations in the health sciences. Less work has been done to understand how these measures compare with widely used survey-based information. Using data from the Copenhagen Network Study, we investigated whether derived survey and smartphone measures on two widely studied concepts; Social integration and Tie strength were associated. The study population included 737 college students (mean age 21.6 years, Standard deviation: 2.6), who were followed with surveys and continuous recordings of smartphone usage over a one-month period. We derived self-reported and smartphone measures of social integration (social role diversity, social network size), and tie strength (contact frequency, duration and tie reciprocity). Logistic regression models were used to assess the associations between smartphone derived and self-reported measures adjusting for gender, age and co-habitation. Larger call and text message networks were associated with having a high self-reported social role diversity, and a high self-reported social contact frequency was likewise associated with having both frequent call and text message interactions, longer call duration and a higher level of reciprocity in call and text message communication. Self-reported aspects of social relations and smartphone measures of social interactions have considerable overlap supporting a measurement of similar underlying concepts.

Loneliness and objectively measured physical capability in middle-aged adults.

Background: Loneliness is associated with poor functional ability in older people. Little is known about this association in the middle-aged. The aim is to investigate if perceived loneliness is associated with lower physical capability among middle-aged men and women and if the associations of loneliness with physical capability interact with socioeconomic position and cohabitation status. Methods: 5224 participants from Copenhagen Aging and Midlife Biobank (CAMB) aged 49-62 years (mean age 54) were included. Handgrip strength (measured by a dynamometer) and maximal number of chair rises in 30 s was recorded. Multivariate linear regression analyses were adjusted for age, occupational social class, cohabitation status, morbidity and personality traits. Results: No association was found between loneliness and physical capability. For example estimates for handgrip strength in 'often' lonely men and women compared with the 'not lonely' were 1.2 kg (95% CI - 0.5;2.9)/1.0 kg (-0.7;2.6). Low occupational social class was associated with poorer physical capability, and living alone was associated with poorer handgrip strength in men [-2.4 kg (95% CI - 3.2;-1.5)] and poorer chair rise test in women [-0.8 rises (95% CI - 1.6;-0.1)]. There was no support for interactions. Conclusion: In contrast to earlier studies among older people, no association between loneliness and physical capability was found in this cohort of middle-aged men and women. Loneliness may not yet have resulted in detectable differences in physical capability in this age group. Further research is needed to clarify if, and at what point in the life course loneliness begins to affect physical capability.

Parental break-ups and stress: roles of age & family structure in 44 509 pre-adolescent children.

Background: Parental break-up is wide spread, and the effects of parental break-up on children's well-being are known. The evidence regarding child age at break-up and subsequent family arrangements is inconclusive. Aim: to estimate the effects of parental break-up on stress in pre-adolescent children with a specific focus on age at break-up and post-breakup family arrangements. Methods: We used data from the Danish National Birth Cohort. Participants included 44 509 children followed from birth to age 11. Stress was self-reported by children at age 11, when the children also reported on parental break-up and post break-up family arrangements. Results: Twenty-one percent of the children had experienced a parental break-up at age 11, and those who had experienced parental break-up showed a higher risk of stress (OR:1.72, 95%CI:1.55;1.91) regardless of the child's age at break-up. Children living in a new family with stepparents (OR = 1.63, 95%CI:1.38;1.92), or shared between the parents (OR = 1.48, 95%CI:1.26;1.75) reported higher stress than children of intact families. Single parent families reported markedly higher stress levels than children in intact families (OR = 2.18, 95%CI:1.90;2.50) and all other family types. Children who were satisfied with their living arrangements post-break-up reported the same stress level as children living in intact families (OR = 1.01, 95%CI:0.86;1.18). Conclusion: Children who experience parental break-up have higher stress levels, also many years after the break-up, and those living in a single parent household post break-up seem to be most vulnerable. Living arrangements post-breakup should be further investigated as a potential protective factor.

Stress and symptoms of depression among medical students at the University of Copenhagen.

OBJECTIVE: This article aims to assess the levels of stress and symptoms of depression among Danish medical students, as well as explore the effect of social support on psychological distress. The results are based on numbers from the follow-up study 'From Student to Graduate' (j.nr 2006-41-6876). MATERIALS AND METHODS: Two dimensions of stress, frequency and perception, were measured on a scale from 0-6. Odds ratios and significance of associations between the various exposure variables and the outcome measure, symptoms of depression, were calculated using multiple logistic regression and Wald tests. RESULTS: 30.5% of the students reported depressive symptoms. Stress frequency measured a mean of 2.26 (SD = 1.35). The mean for stress perception was 2.85 (SD = 1.30). Women reported higher levels of stress and depression compared to male medical students, but the differences were not significant (p > 0.05). Only the dimensions of stress and coping alone were significantly associated with reporting symptoms of depression (p < 0.001). Students coping alone had a two times higher odds ratio for reporting depressive symptoms. CONCLUSIONS: Nearly one third of the participants reported feeling depressed. Stress levels were moderate, but significantly associated with symptoms of depression. The interaction between the stress dimensions and the outcome measure illustrates the importance of stress appraisal. Coping alone with psychological problems was significantly associated with symptoms of depression.

Alcohol consumption and self-reported (SF12) physical and mental health among working-aged men in a typical Russian city: a cross-sectional study.

AIM: To investigate the association between patterns of alcohol consumption and self-reported physical and mental health in a population with a high prevalence of hazardous drinking. DESIGN: Cross-sectional study of an age-stratified random sample of a population register. SETTING : The city of Izhevsk, The Russian Federation, 2008-09. PARTICIPANTS: A total of 1031 men aged 25-60 years (68% response rate). MEASUREMENTS : Self-reported health was evaluated with the SF12 physical (PCS) and mental (MCS) component summaries. Measures of hazardous drinking (based on frequency of adverse effects of alcohol intake including hangover, excessive drunkenness and extended episodes of intoxication lasting 2 or more days) were used in addition to frequency of alcohol consumption and total volume of beverage ethanol per year. Information on smoking and socio-demographic factors were obtained. FINDINGS : Compared with abstainers, those drinking 10-19 litres of beverage ethanol per year had a PCS score 2.66 [95% confidence interval (CI) = 0.76; 4.56] higher. Hazardous beverage drinking was associated with a lower PCS score [mean diff: -2.95 (95% CI = -5.28; -0.62)] and even more strongly with a lower MCS score [mean diff: -4.29 (95% CI = -6.87; -1.70)] compared to non-hazardous drinkers, with frequent non-beverage alcohol drinking being associated with a particularly low MCS score [-7.23 (95% CI = -11.16; -3.29)]. Adjustment for smoking and socio-demographic factors attenuated these associations slightly, but the same patterns persisted. Adjustment for employment status attenuated the associations with PCS considerably. CONCLUSION : Among working-aged male adults in Russia, hazardous patterns of alcohol drinking are associated with poorer self-reported physical health, and even more strongly with poorer self-reported mental health. Physical health appears to be lower in those reporting complete abstinence from alcohol compared with those drinking 10-19 litres per year.

Gender bias in specialty preferences among Danish medical students: a cross-sectional study.

INTRODUCTION: Female medical students tend to prefer person-oriented specialties characterized by close doctor-patient contact and aspects of care. Conversely, male medical students tend to seek towards specialties with elements of autonomy, technology and "action" . Furthermore, female doctors will outnumber male doctors in Denmark by 2017 and this may have implications for the availability of specialized doctors. MATERIAL AND METHODS: Data derives from a baseline questionnaire pertaining to a Danish follow-up study. A total of 561 first year medical students enrolled in 2006 and 2007 answered the questionnaire. Binary logistic regression analysis was used to calculate odds ratio estimates of the relationship between gender and specialty preference. Variables measuring self-image were included in the analysis as potential mediators. RESULTS: 47% female and 19% male students pursued personoriented specialties and 46% female and 68% male students pursued technique-oriented specialties. More female students pursued technique-oriented specialties than in 1992. Female students have 69% less probability of choosing a technique-oriented specialty than males. This association is mediated by lack of self-confidence. CONCLUSION: If specialty preferences are persistent during medical school, the results suggest that we will face more difficulties recruiting males to person-oriented specialties than females to technique-oriented specialties in the future. Furthermore, when addressing students' specialty preferences, we should consider both self confidence and gender. FUNDING: not relevant. TRIAL REGISTRATION: not relevant.

Female medical students are estimated to have a higher risk for developing eating disorders than male medical students.

INTRODUCTION: Studies show that university students are at risk for eating disorders. However, risk behaviour has not been studied among Danish medical students, nor have the gender differences in risk behaviour been described in a Danish context. MATERIAL AND METHODS: All first-year medical students (n = 979) received a questionnaire related to body perception, exercise habits, eating habits, height and weight in the fall of 2006 and 2007. The response rate was 57% (n = 561). The gender distribution of the study population was 71.8% females and 28.2% males and the average age was 21.5 years. RESULTS: More males (89.8%) than females (73.1%) were satisfied with their body and more females (34.8%) than males (10.9%) felt too fat. More females (42.7%) than males (19.9%) felt guilty when eating unhealthy food. 2.3% (all females) claimed to feel anxiety when they were about to eat. More males (48.4%) than females (28.6%) stated that they could not keep themselves from exercising. 13.5% of the underweight females (body mass index < 20 kg/m²) felt too fat, while none of the underweight males had this perception. In average, females and males displayed 2.8 and 2.1 risk behaviours, respectively. CONCLUSION: Female medical students have a drive for thinness and male medical students want to be muscular. More female than male students have a negative body perception. Female medical students are estimated to have a higher risk for developing eating disorders than male students. Future research in this area should address the causes of such behaviour.