Season of birth interacts with measures of inbreeding in multiplex schizophrenia pedigrees: evidence from genetic isolates in Daghestan

While the season-of-birth effect is one of the most consistent epidemiological features of schizophrenia, there is a lack of consistency with respect to the interaction between season of birth and family history of schizophrenia. Apart from family history, measures related to consanguinity can be used as proxy markers of genomic heterogeneity. Thus, these measures may provide an alternate, indirect index of genetic susceptibility. We had the opportunity to explore the interaction between season of birth and measure of consanguinity in well-described genetic isolates in Daghestan, some of which are known for their relatively high prevalence of schizophrenia. Our previous population-genetic study showed Daghestan has an extremely high genetic diversity between the ethnic populations and a low genetic diversity within them. The isolates selected for this study include some with more than 200 and some with less than 100 generations of demographical history since their founding. Based on pedigrees of multiply-affected families, we found that among individuals with schizophrenia, the measure of consanguinity was significantly higher in the parents of those born in winter/spring compared to those born in summer/autumn. Furthermore, compared to summer/autumn born, winter/spring born individuals with schizophrenia had an earlier age-of-onset, and more prominent auditory hallucinations. Our results suggest that the offspring of consanguineous marriages, and thus those with reduced allelic heterogeneity, may be more susceptible to the environmental factor(s) underpinning the season-of-the effect in schizophrenia.     

The Pars Tuberalis: The Missing Link in the Photoperiodic Regulation of Prolactin Secretion?

The endocrine function of the pars tuberalis of the pituitary gland has been an enigma for many years. Recent work suggests that one of its primary functions in seasonal mammals is to mediate photoperiodically regulated changes in prolactin secretion via an unidentified factor called tuberalin.     

Seasonal Changes in the Incidence of Transient Global Amnesia

MethodsEvery patient with acute presentation of amnesia at our medical center is hospitalized for observation and evaluation. We reviewed the monthly occurrence of TGA in our patient population between 2000 and 2014, and compared this to non-TGA hospitalizations during the same time period.ResultsDuring the analysis period, 154 patients who met the criteria for TGA were hospitalized, as well as 259,007 non-TGA hospitalizations. The annual occurrence of TGA ranged from 5 to 16 hospitalizations. There were 91 TGA events in women and 63 in men, in subjects aged 62.8±10.6 years (mean±SD). The incidence was maximal during December [odds ratio (OR)=2.83, 95% confidence interval (CI)=1.20–6.67] and March (OR=2.77, 95% CI=1.17–6.56), and minimal from April to August. The incidence exhibited an increase followed by a decrease from October to February. A seasonal trend was observed as well, with incidence peaks occurring in winter (OR=1.82, 95% CI=1.12–2.96) and spring (OR=1.80, 95% CI=1.10–2.94).ConclusionsOur findings suggest that the incidence of TGA exhibits seasonal variations. This observation may help to improve the understanding of the pathophysiology underlying TGA.     

Seasonal variation of peptic ulcer disease,peptic ulcer bleeding,and acute pancreatitis: A nationwide population-based study using a common data model

Although gastrointestinal diseases are reported at various times throughout the year, some particular seasons are associated with a higher incidence of these diseases. This study aimed to identify the seasonal variations of peptic ulcer (PU), peptic ulcer bleeding (PUB), and acute pancreatitis (AP) in South Korea.We conducted a retrospective, observational cohort study of all subjects aged >18 years between 2012 and 2016 using the Health Insurance Review and Assessment-National Patient Samples database, previously converted to the standardized Observational Medical Outcomes Partnership-Common Data Model. We assessed the overall seasonal variations of PU, PUB, and AP and further analyzed seasonal variations according to age and sex subgroups.In total, 14,626 patients with PU, 3575 with PUB, and 9023 with AP were analyzed for 5 years. A clear seasonal variation was noted in PU, with the highest incidence rate during winter, the second highest during spring, the third highest during summer, and the lowest incidence during autumn for 5 years (P < .001). PUB also showed significant seasonal fluctuations, with winter peak for 4 years, except 1 year, which had a spring peak (P < .001). However, AP showed no clear seasonal variations (P = .090). No significant differences in the seasonal variation of PU, PUB, and AP were observed according to sex and age subgroups (<60 years vs ≥60 years).Seasonal variation of PU and PUB should be considered when determining allocation of available health care resources.     

Seasonality of fetal trisomy 21 – have ambient air pollutants played a role?

Objective: To examine the seasonality of fetal trisomy 21 and its relationship with ambient air pollutants.

Methods: The averaged incidence by month-of-conception of the 113 cases (2002–2009) in our registry was correlated with month of conception and monthly ambient levels of nitrogen oxides (NOx, NO and NO₂), sulfur dioxide, carbon monoxide, and ozone as reported by the Hong Kong Environmental Protection Department at the month of, and four-week after, conception.

Results: The incidence was highest in February (3.45/1000 births) and lowest in October (1.28/1000 births), and showed a significant difference (p?=?0.003) and positive correlation (p?=?0.003) from winter to autumn. It was also correlated with NO (p?=?0.017) and inversely with ozone (p?=?0.014) at conception.

Conclusions: Seasonal variation in incidence of fetal trisomy 21 was correlated with ambient levels of nitric oxides and ozone. The role of environmental pollutants on fetal aneuploidy warrants further investigation.     

Incidence of Type 1 (insulin-dependent) diabetes mellitus in Catalonia, Spain

Summary The incidence of Type 1 (insulin-dependent) diabetes mellitus was prospectively evaluated in Catalonia, Spain in patients up to 30 years of age during the period 1987–1990. The population at risk (0–29 years) consisted of 2,690,394 inhabitants (total population of Catalonia 5,978,638). All the cases were independently identified from four sources: endocrinologists, sales of blood glucose monitors and insulin pen injectors, diabetes societies and diabetic summer camps. The degree of ascertainment was 90.1 %. The overall observed incidence rate was 10.7 per 100,000 per year, being 11.5 per 100,000 per year in the 0–14 age group. The incidence in males (12.0 per 100,000 per year) was higher than in females (9.3 per 100,000 per year), with a male/female ratio of 1.36/l. The sex differences were only present in cases over 14 years of age. Age specific incidence rates per 100,000 per year were 4.4 (confidence interval 95%: 3.2–5.7) in the age group 0–4, 9.9 (8.5–11.4) in 5–9, 17.5 (15.7–19.4) in 10–14, 11.4 (9.9–13.0) in 15–19, 11.3 (9.7–13.0) in 20–24 and 8.5 (7.2–9.9) in 25–29. There was a seasonal onset pattern, with the highest incidence in winter (December–February). We conclude that the incidence of Type 1 diabetes observed in Catalonia during the period 1987–1990 is higher than that recently reported in other Mediterranean countries. This study offers the first standardized data on Type 1 diabetes incidence in Catalonia, including cases up to 30 years, and contributes to the knowledge of the epidemiology of diabetes in South Europe.     

Seasonal changes in melatonin concentrations in female Iberian red deer (Cervus elaphus hispanicus)

In deer, most of the earlier investigations on pineal function examined the effects of artificial photoperiods or the administration of melatonin to manipulate reproduction. However, endogenous melatonin rhythms have not been studied in red deer. Thus, we monitored seasonal changes in plasma melatonin concentrations in 16 adult female Iberian red deer living in outdoor enclosures. Blood was sampled on the day of each seasonal change every 3-4 hr overnight and 1 hr before and after sunset and sunrise. In addition, in six of the previous hinds, blood sampling during the hour prior and after sunset and sunrise was collected every 20 min. Significant differences were found both in amplitude and duration of the nocturnal plasma melatonin profiles in the four seasonal changes (P < 0.01). The nocturnal mean level of melatonin, the duration of nocturnal secretion levels and maximal concentrations were significantly higher at the winter solstice than in summer solstice or equinoxes (P < 0.05). Moreover, the mean overnight concentrations were significantly higher at the spring equinox and winter solstice than during the summer solstice and autumn equinox (P < 0.05). A pronounced elevation from low levels was recorded 1 hr after sunset, remained elevated during the hours of darkness and declined to low levels 1 hr after dawn. Concentrations close to sunrise were higher than those near sunset at all changes of season (P < 0.05). These results show for the first time in red deer that the pineal gland of the adult female is highly responsive to both daily and seasonal changes in natural environmental illumination, although overnight levels lasted longer than the photoperiodic night is all cases, particularly at the winter solstice.     

Temporal integration of melatonin infusion duration: signal averaging versus frequency dependence

Day length affects somatic and reproductive physiology of Siberian hamsters via regulation of the duration of nocturnal pineal melatonin secretion. Nightly 'long' (e.g. 12 hr) or 'short' (e.g. 6 hr) melatonin signals inhibit or stimulate gonadal growth, respectively. When long and short signals are presented in combination, however, neuroendocrine mechanisms exhibit a frequency-dependent response, stimulating gonadal growth only if short signals are presented every second night or more frequently. The present experiments further assessed formal models for the temporal integration of melatonin signals changing abruptly in duration from night to night. Photo-inhibited Siberian hamsters were housed in constant light and infused subcutaneously with various combinations of nightly short or long melatonin signals according to one of the several regimes that varied the frequency of short melatonin signal occurrence, average duration of the nightly melatonin signal, or both. Six weeks of nightly alternating short and long signals yielded different gonadal responses depending on the average melatonin signal duration. Moreover, when average melatonin signal duration was held constant between groups, gonadal stimulation was independent of the frequency of the constituent melatonin signals except when the duration of the short signal was reduced to 3 hr. Thus, neuroendocrine mechanisms do not solely categorize melatonin signals as either long or short but attend also to the duration of each component signal. In the majority (six of seven) of infusion regimes, reproductive responses to chimeric patterns of long and short melatonin signals were compatible with a simple signal-averaging mechanism.