Global Trends in the Prevalence of Alcohol Consumption Among School-Going Adolescents Aged 12-15 Years.

PURPOSE: Adolescent alcohol consumption is detrimental to multiple facets of health. However, there is a scarcity of data available on time trends in adolescents' alcohol consumption particularly from non-Western countries and low- and middle-income countries. Thus, we examined the temporal trend of alcohol use in a large representative sample of school-going adolescents aged 12-15 years from 22 countries in Africa, Asia, and the Americas. METHODS: Data from the Global School-based Student Health Survey were analyzed. Alcohol consumption referred to consuming alcohol on at least one day in the past 30 days. Crude linear trends of past 30-day alcohol consumption by country were assessed by linear regression models. RESULTS: Data on 135,426 adolescents aged 12-15 years were analyzed [mean (standard deviation) age 13.8 (1.0) years; 52.0% females]. The overall mean prevalence of past 30-day alcohol consumption was 14.1%. Of the 22 countries included in the study, increasing, decreasing, and stable trends were observed in 3, 8, and 11 countries, respectively. Specifically, significant increases were observed in Benin between 2009 (16.1%) and 2016 (38.6%), Myanmar between 2007 (0.9%) and 2016 (3.6%), and Vanuatu between 2011 (7.6%) and 2016 (12.2%). The most drastic decrease was observed in Samoa between 2011 (34.5%) and 2017 (9.8%), but the rate of decrease was modest in most countries. DISCUSSION: Among school-going adolescents, decreasing trends in alcohol consumption were more common than increasing trends, but the rate of decrease was limited in most countries, suggesting that more global action is required to curb adolescent alcohol consumption.

Binding pattern of 125iodine thyroxine and tri-iodothyronine in skin and liver tissues of spotted munia, Lonchura punctulata: co-relation to seasonal cycles of breeding and molting.

Prevalent notion about thyroid hormones is that thyroxine (T4) is a mere precursor and physiological effects of thyroid hormones are elicited by tri-iodothyronine (T3) after mono-deiodination of T4. Earlier studies on feather regeneration and molt done on spotted munia L. punctulata suggest that T4 (mono-deiodination suppressed by iopanoic acid and thyroidectomized birds) is more effective than T3 in inducing feather regeneration. The binding pattern of 125I labeled T4 and T3 has been investigated in the nuclei prepared from skin and liver tissues (samples obtained during different months) of spotted munia using scatchard plot analysis. The results show that binding capacity (B(max)--pmole/80 microgm DNA) of 125I-T3 to nuclei of skin was significantly higher in November as compared to April and June, whereas the binding affinity (Kd-10(-9)M(-1)) was significantly lower in November as compared to April and June. During November, B(max) for binding of T3 and T4 did not vary in liver and skin nuclei but Kd varied significantly. Binding capacity of 125I- T3 to skin and liver did not vary but binding affinity of 125I- T4 to skin was approximately 7 times higher than that of liver. The results suggest that T4 does show a variation in binding pattern that co-relates to the molting pattern of spotted munia. These variations might play important role in different physiological phenomenon in this tropical bird. The experiments do point towards the possibility of independent role of T4 as a hormone, however, further experiments need to be done to ascertain the role of T4 in this model and work out the exact molecular mechanism of action.

Daily increments of light hours near vernal equinox synchronize circannual testicular cycle of tropical spotted munia.

In some long-lived organisms, particularly in tropical birds and migrants that spend part of the year close to the equator, endogenous circannual rhythms have been demonstrated in seasonal events like reproduction, molt, and migration. These, like the circadian rhythms, are expressed only in constant conditions of illumination with a periodicity deviating from 1 yr. If birds followed this periodicity, they would soon be out of phase with the annual calendar and perish and, therefore, they would need to be synchronized. However, almost nothing is known as to how synchronization is achieved in birds. Herein, with the help of a suitable model, viz., the tropical spotted munia and long-term experiments conducted in series over a 5-yr period, we provide direct evidence for the first time indicating that the segment of annual photocycle with maximal rate of increase prior to vernal equinox (approximately between mid-February and mid-March) synchronizes the circannual reproductive cycle with the monsoon period of ample food supply through a phase delay. Data also indicate, contrary to the prevalent view, that birds in the tropics can perceive minor changes in day-length, that birds respond to progressive changes in day-length as distinct from responding to fixed photoperiods of particular durations, and that birds can actually distinguish the quality of the environmental signal, viz., vernal equinox from early spring, or increasing days of spring from decreasing days of autumn. The underlying mechanisms, although yet to be identified, appear to involve a gonado-inhibitory rather than the conventional gonado-stimulatory response to increasing day-length. The photoperiodic responses of spotted munia are distinctly different from that of any "long-day" birds described thus far and do not conform to the prevalent "circadian coincidence" hypothesis of photoperiodism.