Bipolar disorder is a multifactorial disorder influenced by multiple genetic and environmental factors.There is limited understanding of how non-genetic factors may impact the age of onset of bipolar disorder

To study the age of onset of bipolar disease in Tunisia (where the average duration of sunshine is 8 hours/day) and compare it to the age of onset in countries with a lower duration of sunshine (Germany 0.17h/day; Norway 1.40h/day).

We conducted a retrospective study of 100 patients with bipolar disorder type I followed at the psychiatric department Aziza Othmana at Razi hospital.The data collection was done using a pre-established paper form exploring sociodemographic and clinical data.The duration of sunshine was estimated according to the average number of hours of sunshine per day in each country collected through meteorological sites.

Our population was predominantly male (60%) with a mean age of 48.7 years.The first episode was manic in 76% of cases. The mean age of onset in our sample was 25.86 years, with extremes ranging from 13 to 49 years.An early onset (threshold age=21 years) was found in 36% of the Tunisian population. The age of onset was earlier in patients with a family history of bipolar disorder: 22.76 years vs 28.23 years. A late onset (threshold age=37 years) was found in 13% of the Tunisian population.

The study confirmed that there is an inverse relationship between the degree of sunlight and the age of onset of the disease, especially in the presence of a family history of mood disorders

No significant relationships.

To assess vitamin D status and the influence of risk factors such as skin pigmentation and time spent outdoors on hypovitaminosis D among Guatemalan Kekchi and Garifuna adolescents.

Cross-sectional study, with convenient sampling design. Blood samples, anthropometric and behavioural data were all collected during the dry season. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured by RIA.

Communities of Rio Dulce and Livingston, Izabal Province, Caribbean coast of Guatemala, with latitude and longitude of 15°49′N and 88°45′W for Livingston and 15°46′N and 88°49′W for Rio Dulce, respectively.

Eighty-six adolescents, divided evenly by sex and ethnicity, with mean age of 14 years.

Mean (sd) 25(OH)D value was 27·8 (7·2) ng/ml for the total group, with 25·8 (5·9) and 29·8 (7·9) ng/ml, respectively, in Kekchis and Garifunas (P=0·01). Use of vitamin D supplementation, clothing practices and sun protection were not statistically different between groups. Skin area exposed on the day of data collection ranged from 20·0 % minimum to 49·4 % maximum, with mean (sd) exposure of 32·0 (8.5) %. With univariate regression analysis, age (P=0·034), sex (P=0·044), ethnicity (P=0·010), time spent outdoors (P=0·006) and percentage skin area exposed (P=0·001) were predictive. However, multivariate analysis indicated that only sex (P=0·034) and percentage skin area exposed (P=0·044) remained as predictors of 25(OH)D.

Despite residing in an optimal geographic location for sunlight exposure, nearly 65 % of study adolescents were either insufficient or deficient in vitamin D. Correction and long-term prevention of this nutritional problem may be instrumental in avoiding adverse effects in adulthood attributed to low 25(OH)D during adolescence.

Few data exist looking at vitamin D status and bone health in school-aged boys and girls from Saudi Arabia. The present study aimed to determine the extent of poor vitamin D status in school boys and girls aged 6–18 years and to examine if there was any difference in status with age, physical activity and veiling and concomitant effects on bone.

Cross-sectional study.

Jeddah, Kingdom of Saudi Arabia.

A total of 150 boys (7–16 years) and 150 girls (6–18 years) from local schools were divided into age categories: 6–9 years (elementary school); 10–12 years (secondary school); 13–14 years (middle years); 15–18 years (high school).

Vitamin D status was significantly lower in girls than boys in all age groups (P < 0·01), with the 15–18-year-old girls having the lowest level (22·0 (sd 9·4) nmol/l) in comparison to the 15–18-year-old boys (39·3 (sd 14·0) nmol/l) and the 6–9-year-old girls (41·2 (sd 9·3) nmol/l). Parathyroid hormone status was highest in the 15–18-year-old girls in comparison to boys of the same age. A total of 64 % of 15–18-year-old girls had 25-hydroxyvitamin D (25OHD) status <25 nmol/l in comparison to 31 % in the 13–14 years age category, 26 % in the 10–12 years category and 2·5 % in the 6–9 years category. No boys had 25OHD status <25 nmol/l. Fully veiled girls had lower 25OHD status than partly veiled or unveiled girls (P < 0·05). Low 25OHD and high parathyroid hormone was associated with lower bone mass in the 6–9 years and 13–14 years age groups (P < 0·05).

These data suggest significant hypovitaminosis D in older adolescent females, which is a cause for concern given that there is currently no public health policy for vitamin D in the Kingdom of Saudi Arabia.