Experienced poor lighting contributes to the seasonal fluctuations in weight and appetite that relate to the metabolic syndrome

Impacts of temperature and solar radiation changes in northern Europe on key population health behaviors: a scoping review of reviews

AIM

Climate change threatens health directly as well as indirectly through impacts on health-related behaviors. Physical activity, nutrition and sleep are key health-related behaviors for population health. We aimed at elucidating the impacts of climate change which emerge gradually on these three key health-related behaviors, particularly focusing on scenarios and projections relevant to people living in the northern Europe.

METHODS

We conducted a systematic literature search in three different databases in January 2023 to identify English language review articles summarizing the effects of climate change on either physical activity, nutrition, sleep, or their combination.

RESULTS

We identified 15 review articles on the topic. Data on climate change impacts on nutrition and sleep were sparse, and those on physical activity were heterogeneous. The climate in northern Europe will become warmer and sunnier in summer as well as warmer and darker in winter, which will probably increase the level of physical activity, but decrease the consumption of fruits and vegetables, as well as increase the occurrence of sleep disturbances in a population.

CONCLUSIONS

The anticipated changes in physical activity, nutrition and sleep driven by climate change influence population health and call for grass-roots action plans for adaptation.

Association between light exposure and metabolic syndrome in a rural Brazilian town

Context

Metabolic syndrome (MetS) is a complex condition comprising a ‘clustering’ of components representing cardiometabolic risk factors for heart disease and diabetes; its prevalence rate is high and consequences serious. Evidence suggests that light exposure patterns and misalignment of circadian rhythms might contribute to MetS etiology by impacting energy metabolism and glucose regulation.

Objective

We hypothesised that individuals with MetS would show disrupted circadian and sleep parameters alongside differences in light exposure profiles. We investigated this using data from a cohort study in Brazil.

Methods

Data from 103 individuals from the Baependi Heart Cohort Study aged between 50 and 70 were analysed. Motor activity and light exposure were measured using wrist-worn actigraphy devices. Cardiometabolic data were used to calculate the number of MetS components present in each participant, and participants grouped as MetS/non-MetS according to standard guidelines. Between-group comparisons were made for the actigraphy measures; additionally, correlation analyses were conducted.

Results

Motor activity and circadian profiles showed no differences between groups. However, the MetS group presented lower light exposure during the day and higher light exposure at night. Correlation analyses, including all participants, showed that greater daytime light exposure and greater light exposure difference between day and night were associated with reduced MetS risk (a lower number of MetS components). Also, the light exposure difference between day and night correlated with body mass index across all participants.

Conclusions

The observed results suggest a direct association between light exposure and MetS which appears to not be attributable to disruptions in circadian activity rhythm nor to sleep parameters. This link between light exposure patterns and MetS risk could inform possible prevention strategies.

Epigenetics of Metabolic Syndrome as a Mood Disorder

Mood disorders comprise major depressive disorder (MDD), bipolar disorder (BD) and the milder forms of these two disorders. Reccurring MDD is also known as unipolar disorder. The distinction between unipolar and bipolar disorders was first suggested in 1957 by Leonard and was made official after support by several studies in 1980. Indeed, in 150 AD, Aretaeus of Cappadocia wrote “It seems to me that melancholia is the beginning and a part of mania”. Additionally, Kraepelin, who proposed the first medical disease model in psychiatry a century ago, considered recurrent unipolar depression cases under the category of bipolar disorder and conceptualized spectrum disorders. Because today’s classification systems conduct cross-sectional diagnosis, they do not consider family history, long-term characteristics and multidimensional approaches on symptoms. This method prioritizes reliability over validity and it rules out psychiatric disorders in etiology. Actually, a spectrum model which covers physical diseases is conceivable. The concept of epigenetics considers mood disorders, Alzheimer’s disease, attention deficit and hyperactivity disorder, Carney syndrome, multiple endocrine neoplasia type I and II, breast and prostate cancers, carsinoid tumors, cerebrovascular and cardiovascular diseases and metabolic syndrome together. This review addressed the relationship between metabolic syndrome and mood disorders in this context along with genetic, clinical and environmental factors such as climate, geographic factors, migration and changeable lifestyles. Genetic and clinical variables are affective temperament, childhood trauma and use of antidepressants and antipsychotics.

Seasonality, morningness-eveningness, and sleep in common non - communicable medical conditions and chronic diseases in a population

The seasonal pattern for mood and behaviour, the behavioural trait of morningness-eveningness, and sleep are interconnected features, that may serve as etiological factors in the development or exacerbation of medical conditions. Methods: The study was based on a random sample of inhabitants aged 25 to 74 years living in Finland. As part of the national FINRISK 2012 study participants were invited (n=9905) and asked whether the doctor had diagnosed or treated them during the past 12 months for chronic diseases. Results: A total of 6424 participants filled in the first set of questionnaires and 5826 attended the physical health status examination, after which the second set of questionnaires were filled. Regression models were built in which each condition was explained by the seasonal, diurnal and sleep features, after controlling for a range of background factors. Of the chronic diseases, depressive disorder was associated with longer total sleep duration (p<.0001) and poor sleep quality (p<.0001). Of the measurements for health status assessment, none associated with sleep features, but systolic blood pressure yielded significant (p<.0001) associations with both seasonal and diurnal features at large. Conclusion: Sleep quality was the most sensitive probe in yielding associations with chronic diseases in this population-based study. The seasonal variations in mood and social activity, and the ease in getting up and tiredness in the morning were the most sensitive probes in yielding associations with blood pressure and waist circumference. Assessment of sleep quality, seasonal and diurnal features provides thus added value for health surveys of the general population.

Circadian and Metabolic Effects of Light: Implications in Weight Homeostasis and Health

Daily interactions between the hypothalamic circadian clock at the suprachiasmatic nucleus (SCN) and peripheral circadian oscillators regulate physiology and metabolism to set temporal variations in homeostatic regulation. Phase coherence of these circadian oscillators is achieved by the entrainment of the SCN to the environmental 24-h light:dark (LD) cycle, coupled through downstream neural, neuroendocrine, and autonomic outputs. The SCN coordinate activity and feeding rhythms, thus setting the timing of food intake, energy expenditure, thermogenesis, and active and basal metabolism. In this work, we will discuss evidences exploring the impact of different photic entrainment conditions on energy metabolism. The steady-state interaction between the LD cycle and the SCN is essential for health and wellbeing, as its chronic misalignment disrupts the circadian organization at different levels. For instance, in nocturnal rodents, non-24 h protocols (i.e., LD cycles of different durations, or chronic jet-lag simulations) might generate forced desynchronization of oscillators from the behavioral to the metabolic level. Even seemingly subtle photic manipulations, as the exposure to a “dim light” scotophase, might lead to similar alterations. The daily amount of light integrated by the clock (i.e., the photophase duration) strongly regulates energy metabolism in photoperiodic species. Removing LD cycles under either constant light or darkness, which are routine protocols in chronobiology, can also affect metabolism, and the same happens with disrupted LD cycles (like shiftwork of jetlag) and artificial light at night in humans. A profound knowledge of the photic and metabolic inputs to the clock, as well as its endocrine and autonomic outputs to peripheral oscillators driving energy metabolism, will help us to understand and alleviate circadian health alterations including cardiometabolic diseases, diabetes, and obesity.

Sex- and age-specific associations between major depressive disorder and metabolic syndrome in two general population samples in Germany

BACKGROUND AND AIMS

Major depressive disorder (MDD) has been associated with the Metabolic Syndrome (MetS). As previous data strongly suggested sex and age effects on this association, this study aimed to analyse the association between MDD and MetS in two general population samples under explicit consideration of sex and age.

METHODS

This study analysed cross-sectional data based on two independent general population samples: SHIP-0 (n = 4083; 20-81 years; 49.4% male) and SHIP-TREND-0 (n = 3957; 20-83 years; 49.0% male) that were part of the Study of Health in Pomerania. MDD (SHIP-0: 12.6%; SHIP-TREND-0: 27.2%) was assessed using the Composite International Diagnostic-Screener (CID-S) in both samples. Interview assessment of MDD diagnosis according to Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) criteria was performed in SHIP-TREND-0 (18.1% MDD). MetS was defined by abdominal obesity, elevated blood pressure, elevated glucose, elevated triglycerides and reduced high-density lipoprotein cholesterol according to established criteria. Data analysis was performed sex- and age-stratified.

RESULTS

Prevalence of MetS was high in both samples: 19.4% of females and 30.2% of males in SHIP-0 and 22.1% and 33.2% in SHIP-TREND-0, respectively. Effect modifications were observed by sex and age on the association between MDD and MetS. Particularly, younger females (20-49 years) with MDD were more often affected by MetS than younger females without MDD: OR = 2.21 (95% CI = 1.39-3.50). This association vanished in elderly participants (50-82 years).

CONCLUSION

The data suggest that especially younger (presumably pre-menopausal) females with MDD are more likely to have MetS than those without major depressive disorders, and that age extenuates this association.

Major depressive disorder and cardiometabolic disease risk among sub-Saharan African adults

OBJECTIVE

We sought to evaluate the extent to which major depressive disorder (MDD) is associated with cardiometabolic diseases and risk factors.

METHODS

This was a cross-sectional epidemiologic study of 1924 employed adults in Ethiopia. Structured interview was used to collect sociodemographic data, behavioral characteristics and MDD symptoms using a validated Patient Health Questionnaire-9 (PHQ-9) depression scale. Fasting blood glucose, insulin, C-reactive protein, and lipid concentrations were measured using standard approaches. Multivariate logistic regression models were fitted to estimate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

A total of 154 participants screened positive for MDD on PHQ-9 (8.0%; 95% CI: 6.7-9.2%). Among women, MDD was associated with more than 4-fold increased odds of diabetes (OR=4.14; 95% CI: 1.03-16.62). Among men the association was not significant (OR=1.12; 95% CI: 0.63-1.99). Similarly, MDD was not associated with metabolic syndrome among women (OR=1.51; 95% CI: 0.69-3.29) and men (OR=0.61; 95% CI: 0.28-1.34). Lastly, MDD was not associated with increased odds of systemic inflammation.

CONCLUSION

The results of our study do not provide convincing evidence that MDD is associated with cardiometabolic diseases among Ethiopian adults. Future studies need to evaluate the effect of other psychiatric disorders on cardiometabolic disease risk.

Illness Attitudes Associated with Seasonal Depressive Symptoms: An Examination Using a Newly Developed Implicit Measure

The Dual Vulnerability Model of seasonal depression posits that seasonal vegetative symptoms are due to a physiological vulnerability, but cognitive and mood symptoms are the result of negative appraisal of vegetative changes. In addition, rumination may be associated with stronger negative attitudes toward vegetative symptoms. This is the first study to examine implicit attitudes toward vegetative symptoms. We hypothesized that illness attitudes about fatigue moderate the relationship between the severity of vegetative symptoms and the severity of cognitive symptoms and that the illness attitudes are associated with rumination. This study also developed an implicit method to assess the appraisal of fatigue as indicating illness. Results supported both hypotheses. Illness attitudes toward fatigue moderated the relationship between vegetative symptoms and cognitive symptoms. Ruminative response style was positively associated with implicit illness attitudes towards fatigue. The study provides support for the role of negative appraisals of vegetative symptoms in the development of cognitive and mood seasonal depressive symptoms.

Bidirectional association between depression and metabolic syndrome: a systematic review and meta-analysis of epidemiological studies

OBJECTIVE

Epidemiological studies have repeatedly investigated the association between depression and metabolic syndrome (MetS). However, the results have been inconsistent. This meta-analysis aimed to summarize the current evidence from cross-sectional and prospective cohort studies that evaluated this association.

RESEARCH DESIGN AND METHODS

MEDLINE, EMBASE, and PsycINFO databases were searched for articles published up to January 2012. Cross-sectional and cohort studies that reported an association between the two conditions in adults were included. Data on prevalence, incidence, unadjusted or adjusted odds ratio (OR), and 95% CI were extracted or provided by the authors. The pooled OR was calculated separately for cross-sectional and cohort studies using random-effects models. The I(2) statistic was used to assess heterogeneity.

RESULTS

The search yielded 29 cross-sectional studies (n = 155,333): 27 studies reported unadjusted OR with a pooled estimate of 1.42 (95% CI 1.28-1.57; I(2) = 55.1%); 11 studies reported adjusted OR with depression as the outcome (1.27 [1.07-1.57]; I(2) = 60.9%), and 12 studies reported adjusted OR with MetS as the outcome (1.34 [1.18-1.51]; I(2) = 0%). Eleven cohort studies were found (2 studies reported both directions): 9 studies (n = 26,936 with 2,316 new-onset depression case subjects) reported adjusted OR with depression as the outcome (1.49 [1.19-1.87]; I(2) = 56.8%), 4 studies (n = 3,834 with 350 MetS case subjects) reported adjusted OR with MetS as the outcome (1.52 [1.20-1.91]; I(2) = 0%).

CONCLUSIONS

Our results indicate a bidirectional association between depression and MetS. These results support early detection and management of depression among patients with MetS and vice versa.

Circadian desynchrony and metabolic dysfunction; did light pollution make us fat?

Circadian rhythms are daily oscillations in physiology and behaviour that recur with a period of 24h, and that are entrained by the daily photoperiod. The cycle of sunrise and sunset provided a reliable time cue for many thousands of years, until the advent of artificial lighting disrupted the entrainment of human circadian rhythms to the solar photoperiod. Circadian desynchrony (CD) occurs when endogenous rhythms become misaligned with daily photoperiodic cycles, and this condition is facilitated by artificial lighting. This review examines the hypothesis that chronic CD that has accompanied the availability of electric lighting in the developed world induces a metabolic and behavioural phenotype that is predisposed to the development of obesity. The evidence to support this hypothesis is based on epidemiological data showing coincidence between the appearance of obesity and the availability of artificial light, both geographically, and historically. This association links CD to obesity in humans, and is corroborated by experimental studies that demonstrate that CD can induce obesity and metabolic dysfunction in humans and in rodents. This association between CD and obesity has far reaching implications for human health, lifestyle and work practices. Attention to the rhythmicity of daily sleep, exercise, work and feeding schedules could be beneficial in targeting or reversing the modern human predisposition to obesity.

ARNTL (BMAL1) and NPAS2 gene variants contribute to fertility and seasonality

BACKGROUND

Circadian clocks guide the metabolic, cell-division, sleep-wake, circadian and seasonal cycles. Abnormalities in these clocks may be a health hazard. Circadian clock gene polymorphisms have been linked to sleep, mood and metabolic disorders. Our study aimed to examine polymorphisms in four key circadian clock genes in relation to seasonal variation, reproduction and well-being in a sample that was representative of the general population, aged 30 and over, living in Finland.

METHODOLOGY/PRINCIPAL FINDINGS

Single-nucleotide polymorphisms in the ARNTL, ARNTL2, CLOCK and NPAS2 genes were genotyped in 511 individuals. 19 variants were analyzed in relation to 31 phenotypes that were assessed in a health interview and examination study. With respect to reproduction, women with ARNTL rs2278749 TT genotype had more miscarriages and pregnancies, while NPAS2 rs11673746 T carriers had fewer miscarriages. NPAS2 rs2305160 A allele carriers had lower Global Seasonality Scores, a sum score of six items i.e. seasonal variation of sleep length, social activity, mood, weight, appetite and energy level. Furthermore, carriers of A allele at NPAS2 rs6725296 had greater loadings on the metabolic factor (weight and appetite) of the global seasonality score, whereas individuals with ARNTL rs6290035 TT genotype experienced less seasonal variation of energy level.

CONCLUSIONS/SIGNIFICANCE

ARNTL and NPAS2 gene variants were associated with reproduction and with seasonal variation. Earlier findings have linked ARNTL to infertility in mice, but this is the first time when any polymorphism of these genes is linked to fertility in humans.

CLOCK is suggested to associate with comorbid alcohol use and depressive disorders

Background

Depression and alcohol abuse or dependence (AUD) co-occur in the general population more frequently than expected by chance. Alcohol use influences the circadian rhythms generated by the central pacemaker in the suprachiasmatic nucleus, and circadian rhythm alterations in turn are common in depressive disorders as well as among persons addicted to alcohol.

Methods

32 SNPs in 19 circadian clockwork related genes were analyzed using DNA from 76 individuals with comorbid depression and AUD, 446 individuals with AUD and 517 healthy controls with no psychiatric diagnosis. The individuals participated in a nationwide health examination study, representative of the general population aged 30 and over in Finland.

Results

The CLOCK haplotype TTGC formed by SNPs rs3805151, rs2412648, rs11240 and rs2412646, was associated with increased risk for comorbidity (OR = 1.65, 95% CI = 1.14-2.28, P = 0.0077). The SNPs of importance for this suggestive association were rs2412646 and rs11240 indicating location of the functional variation in the block downstream rs2412648. There was no indication for association between CLOCK and AUD.

Conclusion

Our findings suggest an association between the CLOCK gene and the comorbid condition of alcohol use and depressive disorders. Together with previous reports it indicates that the CLOCK variations we found here may be a vulnerability factor to depression given the exposure to alcohol in individuals having AUD.