Sex-specific association of exposure to bedroom light at night with general and abdominal adiposity in young adults.

Experimental animal studies and limited epidemiologic evidence among elder population suggest that exposure to light at night (LAN) may be obesogenic. Nevertheless, little is known about the possible impact of bedroom LAN exposure on subsequent adiposity and the distribution pattern of the accumulated fat, especially in younger population. Here, we estimated longitudinal associations of objectively assessed bedroom LAN exposure with general and abdominal adiposity among young adults. We measured 2-night bedroom LAN exposure using a portable illuminometer in a cohort of young adults (n = 482). Body composition using multifrequency bioelectrical impedance analysis was evaluated at baseline and 1-year follow-up visit. Significant increases in fat mass (2.4 kg, P = 0.015 in male; 1.9 kg, P < 0.001 in female), visceral fat area (10.7 cm2, P < 0.001 in male; 5.0 cm2, P = 0.01 in female), waist circumference (3.8 cm, P = 0.039 in male; 2.5 cm, P = 0.047 in female) and percentage of body fat (3.6%, P = 0.002 in male; 3.0%, P = 0.001 in female) were observed among individuals with bedroom LAN higher than 5 lx. Compared to the lowest quartile group of bedroom LAN exposure, the highest quartile group was associated with an increase of 0.64 kg/m2 in BMI (95% CI: 0.18-1.09 kg/m2; P = 0.006) and 1.22 kg increase in fat mass (95% CI: 0.10-2.34 kg; P = 0.025) among female participants, and 10.58 cm2 in visceral fat area (95% CI: 4.85-16.31 cm2; P = 0.001) and 2.59 cm in waist circumference (95% CI: 0.37-4.81 cm; P = 0.023) among male participants. In this cohort of Chinese young adults, significant associations were observed between bedroom LAN exposure and adiposity in a sex- and fat depot-specific fashion. Further intervention and longitudinal studies could help elucidate the actual effects and develop sex-specific strategies against lifetime obesity and related metabolic disorders.

Intergenerational continuity of parent-child separation among mother-offspring dyads: Implication for child cognitive development in rural China.

The labor migration in China often leads to parent-child separation. Research to date has primarily focused on understanding mental and cognitive outcomes for children exposed to parent-child separation, with little consideration for the cumulative effects of intergenerational continuity of parent-child separation. A total of 2729 children between the ages of 4 and 6, along with one parent (primarily mothers, 86.2%) and/or one primary caregiver (if the child is separated from both parents), were recruited in the rural area of Anhui Province, China. A unique subsample of children (n = 249) with persistent experience of parent-child separation or whose mother reported being left behind by her parents during early childhood were enrolled for cognitive assessment. A total of 239 age-, gender- and residence-matched children without any parent-child separation experience were selected as the control group. Child cognitive performance was examined with the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence, Fourth edition (WPPSI-IV). The association between intergenerational continuity of parent-child separation and child cognition was described using multivariate OLS regression models. Compared to mother-offspring dyads without any history of parent-child separation, girls (n = 236/450, 52.4%) who experienced the intergenerational continuity of parent-child separation showed a significant decrease of 5.73 points (95% CI: -9.83, -1.62; p = 0.006) on full-scale intelligence quotient (FSIQ) and a decrease of 5.71 points (95% CI: -9.80, 1.63; p = 0.006) on verbal comprehension index. No similar result was observed in boys. The cumulative effects of parent-child separation among mother-offspring dyads on child cognitive development highlight the need for effective early intervention to break the intergenerational cycle of disadvantage. Sex differences and possible epigenetic mechanisms underlying the intergenerational effects of parent-child separation warrant further investigation.

[A prospective study on the current status of repeated injuries and its risk factors in middle school and college students].

OBJECTIVE: To examine the epidemiological features and relative risk factors of repeated injuries among middle, high and college students in Ma'anshan city of Anhui province. METHODS: A prospective study on repeated injuries for 1-year follow-up period was carried out among 1494 students from 3 middle schools or colleges. Risk factors for repeated injuries were analyzed with multivariate logistic regression model. RESULTS: 799 students suffered 1639 episodes of injuries, with an incidence rate of 53.48%. The repeated group consisted of 200 students who suffered 854 injuries, accounted for 52.10% among the total injuries. RESULTS: from Multi-normal logistic regression analysis showed that male, number of family members of 4 or over, extraversion of character trait, and upper quartile of self-rating anxiety symptoms were the risk factors for the occurrence of repeated injuries. Moderate or well-of family income, mothers with senior high school education, and upper quartile of self-rating depression symptoms were protective factors for repeated injuries. CONCLUSION: Socio-demographic factors and emotional status may predict the occurrence of repeated injuries that called for further study.

[Influence of retrospective time period on reliability of epidemiological survey to injuries].

OBJECTIVE: To analyze the influence of different recall time periods on epidemiological survey of injuries among children and adolescents. METHODS: A study on injuries for 12 months follow-up period was actively surveyed among 4523 pupils selected by cluster sampling from 12 kindergartens, 1 elementary school, 1 junior high school, 1 senior high school and 1 college in Maanshan city in November, 2007 to November, 2008. Injury events were actively surveyed by school doctors or class health workers simultaneously. Participants were divided into three groups, the first group including self-reported injuries by 3-months interval, the second group with self-recalled injuries by 6-months interval and the third group with self-reported injuries in the past 12 months. Validity and reliability of injuries between surveillance injuries and retrospective injuries were compared. RESULTS: The overall rate of injury events was 74.2% and injury events and rate was higher in boys than that in girls (P < 0.01), In total, 6350 injury events were registered for the survey. Compare with surveillance findings, the injury rate declined 0.02% and the number of injuries had a 19 person/time reduction from the retrospective injuries by 3-months interval. The injury rate declined 0.02% and number of injuries reduced 58 person/times from the survey of retrospective injuries by 6-month interval. The rate of injuries declined 8.8% and frequencies had a 505 reduction from data of self-reported injuries in the past 12 months. The largest declines were found for the 3 to 6 year-old age group and for minor injuries. CONCLUSION: The 12-month recall period on underestimate injury rates was compared to the 3-month recall periods and 6-month recall periods. Recall periods of 6 months were recommended to be used in injury survey in children and adolescents.