Excessive screen viewing time by adolescents and body fatness in a developing country: Vietnam.

BACKGROUND AND OBJECTIVES: Screen time among youth has been increasingly recognized as a public health problem because of its link with obesity. This has been demonstrated in many studies conducted in developed countries but few studies have addressed the problem in developing countries, despite an increase literature about the emergence of obesity and a greater access to screen devices in a country like Vietnam. Our study aimed at assessing screen time and its relationship with BMI in adolescents of Ho Chi Minh City (HCMC), Vietnam. METHODS AND STUDY DESIGN: In a cross-sectional study of 2024 junior high school students aged 11-14 of HCMC, students were measured for BMI and questioned on time spent watching television/Video/DVD or using computer for fun. High users were defined as time >=2 h/d. International Obesity Task Force BMI cutoffs were used to define overweight and obesity. RESULTS: Adolescents spent 2.2 h/d in screen time, with higher values for boys than girls (p<0.001). 53.8% of the respondents were high users. Time spent using computers for fun increased with age, and with the household wealthy index. The overall prevalence of overweight and obesity was 21.1%. Using multiple logistic regression, overweight and obesity was higher in boys (adjusted OR=2.66, 95% CI: [2.06; 3.44], p<0.001) and in children aged 11-12 who had a screen time >=2 h/d (adjusted OR=1.48, 95% CI: [1.09; 1.99], p<0.02). CONCLUSIONS: In HCMC, a majority of adolescents spent >=2 h/d on screen time. High screen time is associated with an increased prevalence of overweight and obesity in young adolescents. Public health intervention programs are needed to reduce screen time among youth.

High prevalence of overweight among adolescents in Ho Chi Minh City, Vietnam.

BACKGROUND: Two previous surveys conducted in Ho Chi Minh City revealed an increasing prevalence of overweight and obese adolescents, from 5.9% in 2002 to 11.7% in 2004. From 2004 to 2010, the government set up and implemented health promotion programs to promote physical activity and good nutritional habits in order to prevent overweight and obesity in children and adolescents. Our study aimed to estimate the prevalence of overweight and obesity among adolescents in urban areas of Ho Chi Minh City in 2010. METHODS: A representative sample of 1,989 students aged 11-14 years was selected using a multistage cluster sampling method. 23 schools were randomly selected from the full list of all public junior high schools. In each selected school, 2 classes were chosen at random and all students from the class were examined. Age- and sex-adjusted overweight and obesity were defined using International Obesity Taskforce cut-offs. RESULTS: The prevalences of overweight and obesity were 17.8% and 3.2%, respectively. Prevalences of overweight and obesity were significantly higher in boys (22%, 5.4% ) than in girls (13.3%, 1.3%, p<0.001) and higher in children from districts with a high economic level (20.5% , 3.8% ) than in those from districts with a low economic level (12.1%, 3.8%, p<0.001). Additionally, children living in wealthier families were more overweight and obese than those living in less wealthy families. When using WHO cutoffs, the overall prevalences of overweight and obesity reached 19.6% and 7.9%, respectively. CONCLUSION: Our study's findings suggest that the prevalence of overweight and obesity among secondary school students remains high, especially among boys living in wealthier families. Public health programs should therefore be developed or improved in order to promote good eating habits and physical activity among youth in HCMC.

Prevalence of metabolic syndrome and factor analysis of cardiovascular risk clustering among adolescents in Ho Chi Minh City, Vietnam.

OBJECTIVE: This study aimed to describe the prevalence of metabolic syndrome (MetS) in adolescents of Ho Chi Minh City (HCMC) and to identify components of cardiovascular risk clusters. METHODS: A cross-sectional study was conducted on a representative sample of 693 high-school students 13 to 16 years old in 2007. MetS was defined according to five different definitions: the Pediatric International Diabetes Federation, the Adult Treatment Panel III, and the modified definitions by Cook, Weiss, and De Ferranti. Principal components analysis (PCA) was carried out to cluster risk factors. RESULTS: The prevalence of MetS was high and varied from 3.9% to 12.5%, depending on the criteria used. High levels of triglycerides (or low High Density Lipoprotein Cholesterol) and high blood pressure were the most prevalent components of MetS, while impaired glucose tolerance was the least prevalent. PCA showed three factors in boys (obesity, hypertension, dyslipidemia) that cumulatively explained 64.3%, and four factors in females (obesity, hypertension, dyslipidemia, and hyperglycemia) that accounted for 73.6% of the observed variance of MetS. CONCLUSIONS: The prevalence of MetS in HCMC adolescents was high. Obesity accounts for the maximum variance in clustering and appears to be a more powerful correlate of cardiovascular risk than other variables.

Cohort profile: Ho Chi Minh City Youth Cohort--changes in diet, physical activity, sedentary behaviour and relationship with overweight/obesity in adolescents.

OBJECTIVES: The Ho Chi Minh Youth cohort study aimed to assess the change in nutritional status; indicators of adiposity; diet; physical activity and sedentary behaviours; home, neighbourhood and school microenvironments and their complex relationships in adolescents in urban areas of Ho Chi Minh City. DESIGN: Prospective 5-year cohort. SETTING: Systematic random sampling was used to select 18 schools in urban districts. PARTICIPANTS: Children were followed up over 5 years with an assessment in each year. Consent, from both adolescents and their parents, was required. At baseline, 759 students were recruited into the cohort, and of these students, 740 remained in the cohort for the first round, 712 for the second round, 630 for the third round and 585 for the last round of follow-up. PRIMARY AND SECONDARY OUTCOME MEASURES: Anthropometric measurements were taken using established guidelines. Six main groups of exposure factors including dietary intake and behaviours, physical activity and sedentary behaviours, family social and physical environment, school environment, socioeconomic status and parental characteristics were measured. RESULTS: Retention rate was high (77%). Within 5-year period, the prevalence of combined overweight and obesity using International Obesity Task Force cut-off values increased from 14.2% to 21.8%. Time spent on physical activity decreased significantly in the 5-year period from 87 to 50 min/day. Time spent on sedentary behaviours increased in the 5-year period from 512 to 600 min/day. CONCLUSIONS: The complete data analysis of this cohort study will allow a full exploration of the role of environmental and lifestyle behaviours on adolescent overweight and obesity and also identify the factors most strongly associated with excess weight gain and the appearance of overweight and obesity in different age groups of adolescents from this large city in Vietnam.

Longitudinal physical activity changes in adolescents: Ho Chi Minh City Youth Cohort.

PURPOSE: This study aimed to describe the 5-yr longitudinal change in moderate-to-vigorous physical activity (MVPA) among urban adolescents in Ho Chi Minh City, Vietnam, and to identify individual, family, and environmental factors associated with changes in MVPA. METHODS: The Ho Chi Minh City Youth Cohort is a 5-yr longitudinal cohort with systematic random sampling of 759 students (48% boys) from 18 junior high schools in Ho Chi Minh City, conducted from 2004 to 2009. All measures were taken on five separate occassions. MVPA was assessed by self-report and accelerometry. Data were analyzed using multilevel linear regression models with estimation by generalized linear latent and mixed models. RESULTS: Overall, after adjusting for covariates, students' accelerometer-based MVPA reduced 38% per annum (rate ratio = 0.62, 95% confidence interval (CI) = 0.59-0.64). Boys spent 2.9 times more in MVPA (rate ratio = 2.94, 95% CI = 2.63-3.22) than their female peers. Compared with normal-weight adolescents, overweight and obese adolescents were doing 40% (rate ratio = 0.60, 95% CI = 0.53, 0.67) less MVPA. CONCLUSIONS: MVPA significantly declined among Vietnamese adolescents with age. This finding is similar to those reported among Western adolescents and suggests that strategies to promote physical activity in adolescents are a priority in Vietnam because economic transitioning potentially increases the risk of adopting unhealthy lifestyle behaviors associated with obesity and chronic diseases.

Factors affecting utilization of health care services by mothers of children ill with diarrhea in rural Vietnam.

To examine the use of health services for the treatment of childhood diarrhea in three southern provinces of Vietnam, and identified household, maternal, child and health service characteristics associated with this use, a cross-sectional household survey was conducted between November 1998 and January 1999. Women with a pre-school aged child living at home were the primary respondents for the survey questionnaires. Respondents were asked to recall diarrheal disease events experienced by their child during the two weeks prior to interview, and their responses to these events. Prevalence ratios (PR) were used to identify associations between maternal age, education, occupation, ethnicity, knowledge about diarrhea, feeding practises during diarrhea, household residence and economic status, disease severity, use of oral rehydration solution (ORS), time to nearest health care facility and overall satisfaction with local medical services, and the use of health care services for children ill with diarrhea. The two-week period prevalence of childhood diarrhea was 10% and varied by the province and ethnicity of the child's mother. Forty-three percent of mothers reported using ORS during diarrheal episodes. Seventy percent of mothers sought advice or treatment when their child became ill with diarrhea. After controlling for potential confounders in regression models, maternal ethnicity, maternal high school education (in comparison to no education or incomplete primary education), more severe disease and the use of ORS were factors associated with increased utilization of health care services. There was a low level of the utilization of ORS to treat children with diarrhea, especially by ethnic minority mothers. A high percentage of mothers reported low levels of satisfaction with medical services, especially those from ethnic minorities. Mothers from ethnic minorities and those with lower levels of education were less likely to seek advice or treatment. These findings suggest the need for programs to promote the use of ORS and use of appropriate services for the treatment of childhood diarrheal disease. Interventions are needed to improve the access of ethnic minority children to child health care services for the treatment of diarrhea.