Mediating effects of body composition between physical activity and body esteem in Hong Kong adolescents: a structural equation modeling approach.

This study investigated the mediating role of body mass index (BMI) in the relationship between physical activity and body esteem in adolescents. Nine hundred and five Hong Kong Chinese students aged 12-18 years participated in a cross-sectional study in 2007. Students' BMI was computed as an indicator of their body composition. Their physical activity level and body esteem were examined using the Physical Activity Rating for Children and Youth (PARCY) and Body Esteem Scale (BES), respectively. Structural equation modelling was used to investigate the mediating effects of BMI and physical activity in predicting body esteem, with stratification by sex. The overall fit of the hypothesized models was satisfactory in boys (NFI = 0.94; NNFI = 0.88; CFI = 0.95; RMSEA = 0.07) and girls (NFI = 0.89; NNFI = 0.77; CFI = 0.91; RMSEA = 0.11). When BMI was considered as a mediator, higher physical activity had a significant negative total effect on body esteem in boys, but not in girls. The indirect effect of higher physical activity on body esteem via BMI was positive in boys, but negative in girls. CONCLUSIONS: Regular physical activity may help overweight adolescents, especially boys, improve their body esteem. Kinesiologists and health professionals could explore the use of physical activity prescriptions for weight management, aiming at body esteem improvement in community health programs for adolescents. WHAT IS KNOWN: Among Western adolescents, negative body esteem is more pervasive in girls than in boys. There are consistent findings of the association between higher body mass index and lower body esteem in adolescents, but the association between physical activity and body esteem are equivocal. WHAT IS NEW: A negative association between body mass index and body esteem was found in both Hong Kong adolescent boys and girls. The indirect effect of physical activity on body esteem via body mass index was positive in Hong Kong adolescent boys, but negative in girls.

Views on the peer review system of biomedical journals: an online survey of academics from high-ranking universities.

BACKGROUND: Peer review is the major method used by biomedical journals for making the decision of publishing an article. This cross-sectional survey assesses views concerning the review system of biomedical journals among academics globally. METHODS: A total of 28,009 biomedical academics from high-ranking universities listed by the 2009 Times Higher Education Quacquarelli Symonds (THE-QS) World University Rankings were contacted by email between March 2010 and August 2010. 1,340 completed an online survey which focused on their academic background, negative experiences and views on biomedical journal peer review and the results were compared among basic scientists, clinicians and clinician scientists. RESULTS: Fewer than half of the respondents agreed that the peer review systems of biomedical journals were fair (48.4%), scientific (47.5%), or transparent (25.1%). Nevertheless, 58.2% of the respondents agreed that authors should remain anonymous and 64.4% agreed that reviewers should not be disclosed. Most, (67.7%) agreed to the establishment of an appeal system. The proportion of native English-speaking respondents who agreed that the "peer review system is fair" was significantly higher than for non-native respondents (p = 0.02). Similarly, the proportion of clinicians stating that the "peer review system is fair" was significantly higher than that for basic scientists and clinician-scientists (p = 0.004). For females, (ß = -0.1, p = 0.03), the frequency of encountering personal attacks in reviewers' comments (ß = -0.1, p = 0.002) and the frequency of imposition of unnecessary references by reviewers (ß = -0.06, p = 0.04) were independently and inversely associated with agreement that "the peer review system is fair". CONCLUSION: Academics are divided on the issue of whether the biomedical journal peer review system is fair, scientific and transparent. A majority of academics agreed with the double-blind peer review and to the establishment of an appeal system. Female academics, experience of personal attacks and imposition of unnecessary references by reviewers were related to disagreement about fairness of the peer review system of biomedical journals.

Smoking of parents and best friend--independent and combined effects on adolescent smoking and intention to initiate and quit smoking.

INTRODUCTION: This study investigates the independent and combined effects of smoking of parents and best friend on smoking and the intention to initiate or quit smoking in adolescents. METHODS: In this school-based survey, 6,553 Hong Kong students aged 13-18 reported their demographic characteristics, smoking status of themselves, parents, and best friend; and intention to smoke (initiation among never-smokers and reinitiation among ex-smokers) or quit smoking among current smokers. Logistic regression yielded adjusted odds ratios (AORs) of student smoking (current/ever) and intention to smoke or quit smoking for parental (paternal/maternal/both parents vs. none) and best friend (yes vs. no) smoking. RESULTS: Parental smoking and having a smoking best friend were associated with adolescent current smoking, ever smoking, and intention to initiate smoking. Having a smoking best friend was also associated with reinitiating and quitting smoking. The AORs (95% CI) of current smoking for having a smoking best friend, in addition to smoking father, mother, or both were 19.14 (14.36-25.51), 20.38 (12.42-33.43), and 24.18 (15.89-36.77). The respective AORs of ever smoking were 8.30 (6.74-10.22), 8.92 (5.63-14.12), and 11.99 (8.05-17.87). CONCLUSIONS: Parental smoking and best friend smoking have independent effects on adolescent smoking behaviors. Their combined effects on current and ever smoking were particularly large. Smoking prevention programs should pay special attention to adolescents with both best friend and parents who smoke.

The associations of asthma symptoms with active and passive smoking in Hong Kong adolescents.

BACKGROUND: Tobacco smoke has detrimental effects on the respiratory system. This study investigated the associations of active and passive smoking with asthma symptoms in Hong Kong adolescents. METHODS: A total of 6,494 Hong Kong secondary school students, with a mean ± SD age of 15.0 ± 1.21 years, participated in the Health Related Behavior General Survey in 2000-2001. They reported their demographic factors (sex, age, housing type, district of living), lifestyles (smoking, drinking, extracurricular sports, eating), and asthma symptoms (exercise-induced bronchospasm [EIB] and nocturnal cough) in the questionnaire. In addition, number of smoking parents (none/one/both) and presence of a smoking best friend (yes/no) were assessed. Logistic regression models were used to determine the odds ratios (OR) of frequently having the asthma symptoms for different smoking status of students, parents, and best friend, with adjustment for demographic factors and lifestyles. RESULTS: The prevalence of former, light, and heavy smokers was 17.5%, 7.7%, and 1.0%, respectively. Moreover, 35.1% of the participants had one and 3.8% had 2 parents who smoked. Heavy smokers were more likely to experience EIB with OR (95% CI) of 2.27 (1.30-3.97) and nocturnal cough with OR (95% CI) of 3.45 (1.52-7.81), as well as both symptoms with OR (95% CI) = 4.69 (1.88-11.73) when compared to those who never smoked. The corresponding OR (95% CI) for having at least one smoking parent and a smoking best friend was 1.45 (1.17-1.81), 1.61 (1.06-2.42), and 2.43 (1.37-4.31), when compared with those without a parent or best friend who smoked. CONCLUSIONS: Adolescents who are heavy smokers and having parents and a best friend who smoke are more likely than others to have asthma symptoms. Both active and passive smoking are related to asthma symptoms in adolescents.

Health-related physical fitness and weight status in Hong Kong adolescents.

BACKGROUND: This study was designed to investigate the relation between health-related physical fitness and weight status in Hong Kong adolescents. METHODS: 3,204 students aged 12-18 years participated in the Hong Kong Student Obesity Surveillance (HKSOS) project in 2006-2007. Anthropometric measures (height, weight) and health-related fitness (push-up, sit-up, sit-and-reach, 9-minute run) were assessed. Body mass index (BMI) was computed to classify participants into normal weight, underweight (Grade I, II/III), overweight, and obese groups. The associations of health-related physical fitness with BMI and weight status were examined by partial correlation coefficients and analysis of covariance, respectively. RESULTS: More boys than girls were overweight or obese (18.0% vs 8.7%), but more girls than boys were underweight (22.3% vs 16.7%). Boys performed significantly (P < 0.001) better in sit-up (38.8 vs 31.6 times/min) and 9-minute run (1632.1 vs 1353.2 m), but poorer in sit-and-reach (27.4 vs 32.2 cm) than girls. All four physical fitness tests were significantly positively correlated with each other in both sexes, and BMI was only weakly correlated with sit up and sit-and-reach tests in boys. Decreasing performance (P for trend < 0.05) was observed from normal weight to overweight and obese for push-up, sit-up, and 9-minute run in both sexes. From normal weight to Grade I and Grade II/III underweight, decreasing performance (P for trend < 0.05) for sit-up and sit-and-reach in both sexes and for push-up in boys was observed. CONCLUSIONS: The relations between BMI and health-related physical fitness in adolescents were non-linear. Overweight/obese and underweight adolescents had poorer performance in push-up and sit-up tests than normal weight adolescents. Different aspects of health-related physical fitness may serve as immediate indicators of potential health risks for underweight and overweight adolescents.

Secular trends of sports participation, sedentary activity and physical self-perceptions in Hong Kong adolescents, 1995-2000.

AIM: To assess the 5-year secular changes in sports participation, sedentary activity, and physical self-perceptions among Hong Kong adolescents. METHODS: A total of 2932 and 5692 secondary students, aged 13-18 participated in the Health Related Behavior General (HRBG) Survey in 1995-1996 and 2000-2001, respectively. Extracurricular sports participation at least weekly or as a team member (none, 1-2 events, 3 or more events), sedentary activities (0-1 h/day, 2 h/day or more) including television/video watching and homework were assessed. Additionally, physical self-perceptions, physical fitness (fit/very fit, moderately fit, unfit/very unfit) and body weight (intention to lose weight, satisfied, intention to gain weight) were reported. Secular trends of sports participation, and sedentary activities and physical self-perceptions were assessed. RESULTS: During the 5 years, the prevalence of sports participation (at least weekly or membership) decreased significantly in boys. The prevalence of both TV/video watching and homework for at least 2 h/day increased significantly in both sexes. The prevalence of being unfit/very unfit increased significantly in girls. No significant secular difference in weight perception was observed for both sexes. CONCLUSIONS: Sports participation decreased and sedentary activities increased during the 5-year period. Physical self-perceptions did not change significantly, except an increase in being physically unfit was observed in girls.

Characteristics of overdose and non-overdose suicide attempts in a multi-ethnic Asian society.

BACKGROUND: Overdosing is an accessible method adopted by people attempting suicide in city settings. AIMS: This study aimed to compare the trends and characteristics of people attempting suicide by drug overdose and by other methods in Singapore. METHODS: This study examined the medical records of 628 patients who were admitted to a university hospital in Singapore, between January 2004 and December 2006. Patients were classified as overdose and non-overdose persons attempting suicide for comparisons of demographic and suicidal characteristics. Logistic regression was used to determine the odds ratios of various factors associated with self-perceived lethality of the suicide attempt. Patterns of monthly and weekly variations in the frequencies of suicide attempts were also analyzed. RESULTS: The percentages of Chinese people was higher in the non-overdose group (71.5% vs. 62.9%), while the percentages of Malay and Indian people were higher in the overdose group (31.6% vs. 18.5%). The female gender (OR=0.36, p=0.04) and admission of suicide intention (OR=7.11, p<0.001) were significantly associated with higher perceived lethality of the suicide method in the non-overdose group. Suicide attempts occurred more frequently between May and November, and on Tuesdays. CONCLUSIONS: Gender and ethnic differences between overdose and non-overdose people attempting suicide were found. Temporal variations of suicidal cases were also noted.