The association between partner bereavement and melanoma: cohort studies in the U.K. and Denmark.

BACKGROUND: Psychological stress is commonly cited as a risk factor for melanoma, but clinical evidence is limited. OBJECTIVES: This study aimed to evaluate the association between partner bereavement and (i) first-time melanoma diagnosis and (ii) mortality in patients with melanoma. METHODS: We conducted two cohort studies using data from the U.K. Clinical Practice Research Datalink (1997-2017) and Danish nationwide registries (1997-2016). In study 1, we compared the risk of first melanoma diagnosis in bereaved vs. matched nonbereaved people using stratified Cox regression. In study 2 we estimated hazard ratios (HRs) for death from melanoma in bereaved compared with nonbereaved individuals with melanoma using Cox regression. We estimated HRs separately for the U.K. and for Denmark, and then pooled the data to perform a random-effects meta-analysis. RESULTS: In study 1, the pooled adjusted HR for the association between partner bereavement and melanoma diagnosis was 0·88 [95% confidence interval (CI) 0·84-0·92] across the entire follow-up period. In study 2, we observed increased melanoma-specific mortality in people experiencing partner bereavement across the entire follow-up period (HR 1·17, 95% CI 1·06-1·30), with the peak occurring during the first year of follow-up (HR 1·31, 95% CI 1·07-1·60). CONCLUSIONS: We found decreased risk of melanoma diagnosis, but increased mortality associated with partner bereavement. These findings may be partly explained by delayed detection resulting from the loss of a partner who could notice skin changes. Stress may play a role in melanoma progression. Our findings indicate the need for a low threshold for skin examination in individuals whose partners have died. What is already known about this topic? Psychological stress has been proposed as a risk factor for the development and progression of cancer, including melanoma, but evidence is conflicting. Clinical evidence is limited by small sample sizes, potential recall bias associated with self-report, and heterogeneous stress definitions. What does this study add? We found a decreased risk of melanoma diagnosis, but increased mortality associated with partner bereavement. While stress might play a role in the progression of melanoma, an alternative explanation is that bereaved people no longer have a close person to help notice skin changes, leading to delayed melanoma detection. Linked Comment: Talaganis et al. Br J Dermatol 2020; 183:607-608.

Partner bereavement and risk of psoriasis and atopic eczema: cohort studies in the U.K. and Denmark.

BACKGROUND: Stress is commonly cited as a risk factor for psoriasis and atopic eczema, but such evidence is limited. OBJECTIVES: To investigate the association between partner bereavement (an extreme life stressor) and psoriasis or atopic eczema. METHODS: We conducted cohort studies using data from the U.K. Clinical Practice Research Datalink (1997-2017) and Danish nationwide registries (1997-2016). The exposed cohort was partners who experienced partner bereavement. The comparison cohort was up to 10 nonbereaved partners, matched to each bereaved partner by age, sex, county of residence (Denmark) and general practice (U.K.). Outcomes were the first recorded diagnosis of psoriasis or atopic eczema. We estimated hazard ratios (HRs) and confidence intervals (CIs) using a stratified Cox proportional hazards model in both settings, which were then pooled in a meta-analysis. RESULTS: The pooled adjusted HR for the association between bereavement and psoriasis was 1·01 (95% CI 0·98-1·04) across the entire follow-up. Similar results were found in other shorter follow-up periods. Pooled adjusted HRs for the association between bereavement and atopic eczema were 0·97 (95% CI 0·84-1·12) across the entire follow-up, 1·09 (95% CI 0·86-1·38) within 0-30 days, 1·18 (95% CI 1·04-1·35) within 0-90 days, 1·14 (95% CI 1·06-1·22) within 0-365 days and 1·07 (95% CI 1·02-1·12) within 0-1095 days. CONCLUSIONS: We found a modest increase in the risk of atopic eczema within 3 years following bereavement, which peaked in the first 3 months. Acute stress may play a role in triggering onset of new atopic eczema or relapse of atopic eczema previously in remission. We observed no evidence for increased long-term risk of psoriasis and atopic eczema following bereavement.

Plastic and evolutionary responses to heat stress in a temperate dung fly: negative correlation between basal and induced heat tolerance?

Extreme weather events such as heat waves are becoming more frequent and intense. Populations can cope with elevated heat stress by evolving higher basal heat tolerance (evolutionary response) and/or stronger induced heat tolerance (plastic response). However, there is ongoing debate about whether basal and induced heat tolerance are negatively correlated and whether adaptive potential in heat tolerance is sufficient under ongoing climate warming. To evaluate the evolutionary potential of basal and induced heat tolerance, we performed experimental evolution on a temperate source population of the dung fly Sepsis punctum. Offspring of flies adapted to three thermal selection regimes (Hot, Cold and Reference) were subjected to acute heat stress after having been exposed to either a hot-acclimation or non-acclimation pretreatment. As different traits may respond differently to temperature stress, several physiological and life history traits were assessed. Condition dependence of the response was evaluated by exposing juveniles to different levels of developmental (food restriction/rearing density) stress. Heat knockdown times were highest, whereas acclimation effects were lowest in the Hot selection regime, indicating a negative association between basal and induced heat tolerance. However, survival, adult longevity, fecundity and fertility did not show such a pattern. Acclimation had positive effects in heat-shocked flies, but in the absence of heat stress hot-acclimated flies had reduced life spans relative to non-acclimated ones, thereby revealing a potential cost of acclimation. Moreover, body size positively affected heat tolerance and unstressed individuals were less prone to heat stress than stressed flies, offering support for energetic costs associated with heat tolerance. Overall, our results indicate that heat tolerance of temperate insects can evolve under rising temperatures, but this response could be limited by a negative relationship between basal and induced thermotolerance, and may involve some but not other fitness-related traits.

Temperature and population density effects on locomotor activity of Musca domestica (Diptera: Muscidae).

The behavior of ectotherm organisms is affected by both abiotic and biotic factors. However, a limited number of studies have investigated the synergistic effects on behavioral traits. This study examined the effect of temperature and density on locomotor activity of Musca domestica (L.). Locomotor activity was measured for both sexes and at four densities (with mixed sexes) during a full light and dark (L:D) cycle at temperatures ranging from 10 to 40°C. Locomotor activity during daytime increased with temperature at all densities until reaching 30°C and then decreased. High-density treatments significantly reduced the locomotor activity per fly, except at 15°C. For both sexes, daytime activity also increased with temperature until reaching 30 and 35°C for males and females, respectively, and thereafter decreased. Furthermore, males showed a significantly higher and more predictable locomotor activity than females. During nighttime, locomotor activity was considerably lower for all treatments. Altogether the results of the current study show that there is a significant interaction of temperature and density on daytime locomotor activity of M. domestica and that houseflies are likely to show significant changes in locomotor activity with change in temperature.

Training-induced cortical plasticity compared between three tongue-training paradigms.

The primary aim of this study was to investigate the effect of different training types and secondary to test gender differences on the training-related cortical plasticity induced by three different tongue-training paradigms: (1) therapeutic tongue exercises (TTE), (2) playing computer games with the tongue using the Tongue Drive System (TDS) and (3) tongue-protrusion task (TPT). Forty-eight participants were randomized into three groups with 1h of TTE, TDS, or TPT. Stimulus-response curves of motor evoked potentials (MEPs) and motor cortex mapping for tongue muscles and first dorsal interosseous (FDI) (control) were established using transcranial magnetic stimulation at three time-points: (1) before tongue-training, (2) immediately after training, (3) 1h after training. Subject-based reports of motivation, fun, pain and fatigue were evaluated on 0-10 numerical rating scales after training. The resting motor thresholds of tongue MEPs were lowered by training with TDS and TPT (P<0.011) but not by TTE (P=0.167). Tongue MEP amplitudes increased after training with TDS and TPT (P<0.030) but not with TTE (P=0.302). Men had higher MEPs than women in the TDS group (P<0.045) at all time-points. No significant effect of tongue-training on FDI MEPs was observed (P>0.335). The tongue cortical motor map areas were not significantly increased by training (P>0.142). Training with TDS was most motivating and fun (P<0.001) and TTE was rated the most painful (P<0.001). Fatigue level was not different between groups (P>0.071). These findings suggest a differential effect of tongue-training paradigms on training-induced cortical plasticity and subject-based scores of fun, motivation and pain in healthy participants.

Population viability analysis of American mink (Neovison vison) escaped from Danish mink farms.

The American mink (Neovison vison) was introduced to Danish fur farms in the 1930s. An unknown number of mink have managed to escape these farms over the years. Today feral mink are found in the wild in most parts of Denmark. A population viability analysis (PVA) was performed using VORTEX, a stochastic population simulation software, to 1) predict the viability and potential population expansion from different sizes of founding populations of farm escapees, 2) investigate which parameters mostly affect the viability, 3) assess the effects of continuous escapes on the feral populations and how the feral populations are affected by management programs, and 4) discuss eradication strategies and their efficiency in management of the feral American mink population in Denmark. The simulations showed that juvenile mortality had the greatest effect on population viability followed by fecundity, adult mortality, and initial population size. Populations supplemented yearly by escapees all reached the carrying capacity and gained genetic variability over the years. Harvesting was modeled as the yearly number of mink caught in Denmark. Most of the simulated harvested populations crashed within few years after the first harvesting event. This indicates that the feral number of mink in Denmark is sustained due to supplements from mink farms and no true feral population exists. To manage the number of feral mink in Denmark it is essential to prevent escapees. The eradication effort would be most effective if focused on late summer and autumn when juvenile mink leave the maternal territory.