Background
This study was designed to find out the effect of school based obesity prevention intervention by considering the changes of BMI during both at the time of intervention and post-intervention. Methods: The research was conducted at an elementary school located in Busan metropolitan city, where we measured the height and weight of 260 students at baseline, 6 months after the initiation, and 6 months after the intervention. The students were classified into three weight groups of normal, overweight and obesity according to the age and sex-specific BMI. Results: The BMI decreased or maintained in 60% of the boys and 65% of the girls after the initial six months of the intervention, while after six months from the end of the intervention, BMI increased in 91% of the boys and 83% of the girls. The children's BMI significantly decreased during the intervention (P＜0.01), whereas it significantly increased post intervention (P＜0.05). In the logistic regression model including age, sex, initial BMI, and the follow-up status after the intervention, the increase of BMI by 1 unit was associated with 11% lower odds (95% CI 0.83∼0.98) for BMI decrease and maintenance. Likewise, the increase of age by 1 year was associated with 24% lower odds (95% CI 0.59∼0.98) for BMI decrease and maintenance. However, there was no significant predictors for BMI decrease and maintenance after the intervention. Conclusion: As the positive effect of this intervention for children is not consistent, the research should be more focused in finding out the effective method for prevention of obesity among elementary school children, as a better solution in the longrun. (J Korean Acad Fam Med 2008;29:572-578)

Background
Short-term measurement of heart rate variability is known to be a non-invasive technique to examine autonomic nerve system. Heart rate variability exhibits circadian rhythm according to work/sleep cycle and biological clock. In primary practice, short-term measurement of heart rate variability is usually used during the day. Therefore the aims of this study were to investigate the possibility of differences in heart rate variability between morning and afternoon and also to examine the relationship among associated factors. Methods: Sixty-eight healthy volunteers underwent short- term measurement of heart rate variability on two occasions: in the morning (08：30∼11：00) and in the afternoon (13：30∼16：00). A structured questionnaire was used to access general characteristics, emotion, fatigue and sleeping hours. Results: The mean heart rate was significantly increased and SDNN, RMSSD, TP, HF and VLF were significantly decreased in the afternoon compared to the morning. LF and LF/HF were not changed. The anxiety group, the depression group and the fatigue group showed significantly greater reduction in TP and RMDDS than the control group. Conclusion: In the afternoon, parasympathetic activity and total power were decreased significantly compared to the morning. Short-term heart rate variability should be measured in the same time zone and need to consider food intake effect. Those who complained of anxiety, depression or fatigue were related to much decrease in TP and RMSSD in the afternoon. (J Korean Acad Fam Med 2008;29:579-584)

Background
We aimed to evaluate the effect of school- based obesity prevention and management program applied to adolescents in a middle school on body mass index (BMI), weight-related attitude, eating behavior and physical activity of adolescents. Methods: A total of 664 adolescents (14.7±0.9 years old) in a middle school located in Busan were study subjects. The obesity prevention and management program was conducted for 6 months, from March to September, 2005. Their weight and height were measured and their weight-related attitude, eating habit and physical activity were assessed using a questionnaire at baseline and after 6 months. Their weight status was classified into under-, normal-, and overweight according to their BMI at baseline. Results: The prevalence of underweight and overweight was 6.2% and 19.3%, respectively. Among the adolescents with overweight, the BMI significantly decreased after 6 months compared to the BMI at baseline (P＜0.05), while the BMI was not significantly changed over 6 months among the under- and normal weight groups. The adolescents were more likely to become highly concerned about obesity-related problems (P=0.002) and actively participating in obesity prevention program (P=0.007) after 6 months compared to those attitude at baseline. The BMI significantly decreased in the adolescents whose eating behavior or physical activity were improved compared to their counterparts (P＜0.05). Conclusion: The 6-months program for obesity prevention and management seemed to reduce BMI in overweight adolescents and raise concern about obesity related problems and promote participation in obesity prevention program in adolescents as a whole. Further long-term intervention studies need to be implemented. (J Korean Acad Fam Med 2008;29:585-594)

Background
Neck shoulder pain (NSP) was highly prevalent even among the adolescents in previous Western studies. However, the prevalence among Korean adolescents was seldom studied and the factors associated with NSP were controversial. Methods: A self-administered questionnaire asking the presence of NSP, restriction in daily activities due to NSP, behavioral characteristics, and psychological factors was given to 1,232 adolescent enrolled in high schools. Finally, 1,194 providing adequate responses to the questionnaire were included. NSP occurring once a week or more over the last 6 months was defined as a significant NSP and the association between the significant NSP and the studied variables was estimated using multiple logistic regression analysis. Results: The prevalence of NSP and the significant NSP were 82.9% and 33.4%, respectively. The girls (40.6%) were experiencing the significant NSP more than the boys (26.0%). Restriction in daily activities due to NSP was very common and 74.8% of the girls and 65.2% of the boys reported study disturbance. The factors associated with higher risk significant NSP in the boys were higher BMI (25≥ kg/m²), moderate stress, and fairly poor or poor self-assessed physical condition with odds ratios (95% confidence intervals) of 1.86 (1.02∼3.40), 1.74 (1.03∼2.97), and 2.30 (1.26∼4.19), respectively. In the girls, a longer (＞75% of total sitting time) time of sitting in desk/chair of the inadequate height was associated with a higher risk of the significant NSP (odds ratio: 1.59, 95% confidence interval: 1.05∼2.39). Conclusion: The prevalence of NSP in Korean adolescents was very high, suggesting that active efforts to prevent NSP in Korean adolescents would be needed with a consideration of different risk factors between girls and boys. (J Korean Acad Fam Med 2008;29:595-603)

Background
This study was to verify the necessity of a control program developed to improve compliance, by conducting a research on the status of medication compliance in the elderly with chronic diseases in rural area and analyzing the related variables. Methods: The organized questionnaire and pill-count were used to collect information on personal details, physical status, drugs taken in the elderly over 65 years old suffering from more than two chronic diseases in one rural area. Results: The mean age of the subjects was 73.13±6.36 (65∼93), and the number of the subjects in compliance group was 60 (77.9%) and the accuracy of self-report which was identified by pill-count was 0.86. Polypharmacy and visiting several clinics were the main factors that decided a low- degree of compliance, with OR of 5.92 (95% CI 1.11∼31.44, P=0.037), and 4.25 (95% CI 1.03∼17.53, P=0.045), respectively. Conclusion: Systematic efforts are necessary and plans must be established without delay to increase compliance in the elderly in the rural, expansively to manage chronic diseases in stay-at-home elders. (J Korean Acad Fam Med 2008;29:604-611)

Myalgia, muscle weakness, muscle cramping, muscular rigidity and elevated levels of serum creatinine kinase (CK) are very common in patients with hypothyroidism. However, these symptoms are not clinically serious in most cases and are not found in primary care. So far, 5 Cases with hypothyroid myopathy have been reported in the Korean literature. However, it is not reported that this case has been found in primary care or in periodic health examination. We report a case of hypothyroid myopathy that was presented with exercise-induced myalgia. This case was diagnosed as hypothyroid myopathy through abnormal thyroid function test and elevated levels of serum CK and myoglobin in periodic health examination. Muscle symptoms and laboratory abnormality were improved only with thyroid hormone replacement therapy. (J Korean Acad Fam Med 2008;29:612-616)