Alan C. Tsai

Dieting is more effective in reducing weight but exercise is more effective in reducing fat during the early phase of a weight-reducing program in healthy humans

This study compared the relative effectiveness of two means of energy deficit, food restriction (FR) and increased physical activity (EX), on body weight, body composition and concentrations of serum leptin, insulin, glucose, and lipids in female subjects. Thirteen adult female volunteers participated in a two-phase crossover-treatment study. Each phase involved a 9-day energy deficit period and a 5-day follow up energy repletion period. A 25% energy deficit was achieved by either FR or EX. Baseline values were established prior to phase one. Results showed that FR had greater body weight loss, but less body fat loss compared to EX. FR and EX both reduced serum leptin, insulin, total triacylglycerol, LDL-C and VLDL-C concentrations. However, only EX elevated HDL-C. These effects were reversed during follow up energy repletion. Results suggest that under iso-caloric energy deficit conditions FR is more effective in reducing body weight but EX is more effective in reducing body fat and maintaining lean body mass. EX can lead to a more desirable blood lipid profile than can FR. Thus, it is desirable to include exercise in a weight reduction program.

Associations of BMI, TV-Watching Time, and Physical Activity on Respiratory Symptoms and Asthma in 5th Grade Schoolchildren in Taipei, Taiwan

The study evaluated the associations of body fatness, TV-watching time, and physical activity with the occurrences of asthma and respiratory symptoms in schoolchildren in Taipei, Taiwan. A questionnaire survey was conducted to elicit episodes of respiratory symptoms and data on lifestyle and anthropometric factors in 2290 5th-grade schoolchildren. Results show that overweight was positively associated with 5 of the 7 respiratory symptoms. The risk of having respiratory symptoms increased 47%–94% in overweight schoolchildren. Watching TV ≥ 3 hrs/day was associated with more occurrences of respiratory symptoms (aOR = 1.42–1.90). Physical activity ≥3 times/week was associated with fewer occurrences of respiratory symptoms (aOR = 0.66–0.73). Overweight was positively associated with an increased risk of suspected asthma in boys (aOR = 1.56, 95% CI = 1.07–2.29), but not in girls. In summary, overweight and greater TV-watching time increase the risk of respiratory symptoms, while habitual physical activity decreases the risk of respiratory symptoms. Weight status, sedentary life, and frequency of physical exercise are the factors that can impact on the respiratory health of schoolchildren.

The Association of Diet with Respiratory Symptoms and Asthma in Schoolchildren in Taipei, Taiwan

This study aimed to evaluate the association of diet with respiratory symptoms and asthma in schoolchildren in Taipei, Taiwan. An in-class interview survey elicited experiences of asthma and respiratory symptoms and consumption frequencies of the major food categories in 2290 fifth graders. Respiratory symptoms surveyed included persistent cough, chest tightness, wheezing with cold, wheezing without cold, dyspnea-associated wheezing, and exercise-induced cough or wheezing. Results showed that the consumption of sweetened beverages had the strongest association with respiratory symptoms and was positively associated with six of the seven respiratory symptoms (all p < 0.05). The adjusted odds ratios (aOR) ranged from 1.05 (95% confidence interval (CI = 1.01–1.09) for exercise-induced cough to 1.09 (95% CI = 1.03–1.16) for wheezing without cold. Egg consumption was associated with 5 of the 7 respiratory symptoms. Consumptions of seafood, soy products, and fruits were each negatively associated with one of the seven respiratory symptoms (all p < 0.05). Consumption of seafood was negatively associated with physician-diagnosed asthma and consumptions of sweetened beverages and eggs were positively associated with suspected asthma (p < 0.05). In conclusion, the study suggests that diet is associated with the respiratory symptoms in schoolchildren in Taipei. Consumptions of sweetened beverages and eggs are associated with increased risk of respiratory symptoms and asthma whereas consumptions of soy products and fruits are associated with reduced risk of respiratory symptoms.

Risk Factors for Respiratory Symptoms and Asthma in the Residential Environment of 5th Grade Schoolchildren in Taipei, Taiwan

This study examined the association of residential environmental factors with respiratory symptoms and asthma in 2,290 fifth graders in Taipei, Taiwan. A self-report survey questionnaire elicited experiences of respiratory symptoms, disease history, and characteristics of residential environmental factors from schoolchildren. The proportion of schoolchildren having physician-diagnosed asthma was 9.8% and suspected asthma was 16.1%. The proportions of having respiratory symptoms in the past 12 months ranged from 9.8% for wheezing without a cold to 40.5% for exercise-induced cough. Higher proportions of boys had non-exercise-induced respiratory symptoms, physician-diagnosed asthma, and suspected asthma than girls (p < 0.05). Exposure to odoriferous chemical vapor was significantly associated with all seven respiratory symptoms considered in the study (p < 0.05). After adjusting for confounding factors including residential districts, gender, diagnosed allergy, and parental history of respiratory symptoms, odoriferous chemical vapors, gas leaks, dehumidifier use, presence of cockroaches at home, and leaky water/water puddle at home were significantly associated with the proportions of physician-diagnosed asthma or suspected asthma of the schoolchildren. The adjusted odds ratio (aOR) of physician-diagnosed asthma was 2.35 (95% confidential interval = 1.45–3.82) for odoriferous chemical vapor. The aOR of suspected asthma measure was 2.14 (95% CI = 1.40–3.26) for odoriferous chemical vapor. Odoriferous chemical vapor was the major risk factor of respiratory illness in the residential environment of schoolchildren in Taipei. Other household risk factors included gas leaks, dampness, and cockroaches at home.