METHOD: Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density.
RESULTS: There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001).
CONCLUSION: A large increase in springtime solar insolation may impact the onset of bipolar disorder, especially with a family history of mood disorders. Recent societal changes that affect light exposure (LED lighting, mobile devices backlit with LEDs) may influence adaptability to a springtime circadian challenge.
METHODS: Published literature, information from statistical bureaus, clinician surveys and extrapolation of selected data from the European Union were used to determine the socioeconomic costs of AR and urticaria.
RESULTS: Many patients in Asia suffer from perennial allergies and experience symptoms of AR and urticaria for up to 298 days per year. An estimate of the indirect costs of patients insufficiently treated for AR and urticaria amounts to USD 105.4 billion a year, which equates to USD 1,137-2,195 per patient due to absenteeism and presenteeism. Adherence to guideline-approved treatment can lead to estimated savings of up to USD 104 billion.
CONCLUSIONS: The current study suggests that within Asia, the socioeconomic impact of AR and urticaria is similar to that seen in the European Union in spite of the lower wages in Asia. This is due to the mainly perennial allergens prevailing in Asia, whereas the sensitization patterns observed in the European Union are dominated by seasonal exposure to pollen. These results underline the need for governmental initiatives to increase public awareness on the prevention and treatment of these and other allergic diseases as well as greater research funding and large-scale studies to reduce their growing socioeconomic burden in coming years.
METHODS: To understand the regulation by temperature of leaf phenology in tropical trees, we performed daily observations of leaf production under rainfall-independent conditions using saplings of Shorea leprosula and Neobalanocarpus heimii, both species of Dipterocarpaceae, a dominant tree family of Southeast Asia. We analyzed the time-series data obtained using empirical dynamic modeling (EDM) and conducted growth chamber experiments.
RESULTS: Leaf production by dipterocarps fluctuated in the absence of fluctuation in rainfall, and the peaks of leaf production were more frequent than those of day length, suggesting that leaf production cannot be fully explained by these environmental factors, although they have been proposed as regulators of leaf phenology in dipterocarps. Instead, EDM suggested a causal relationship between temperature and leaf production in dipterocarps. Leaf production by N. heimii saplings in chambers significantly increased when temperature was increased after long-term low-temperature treatment. This increase in leaf production was observed even when only nighttime temperature was elevated, suggesting that the effect of temperature on development is not mediated by photosynthesis.
CONCLUSIONS: Because seasonal variation in temperature in the tropics is small, effects on leaf phenology have been overlooked. However, our results suggest that temperature is a regulator of leaf phenology in dipterocarps. This information will contribute to better understanding of the effects of climate change in the tropics.