Familial interactions and physical, lifestyle, and dietary factors to affect bone mineral density of children in the KNHANES 2009-2010.

We examined familial bone mineral density (BMD) interactions between parents and children and lifestyle factors affecting BMD in the Korean general population of children under 20 and parents under 50 years of age. This cross-sectional study included 2,453 participants (667 daughters, 705 sons, 719 mothers, and 362 fathers) in the 2009-2010 Korean National Health and Nutrition Examination Survey. We calculated prevalence ratios and 95 % confidence intervals for BMD values of whole femur, femur neck, lumbar spine, and whole body excluding the head being in the low tertile in adolescents according to parental BMD tertile after adjusting for physical, lifestyle, and dietary factors. For daughters and sons, there were significant differences in BMD at the four bone sites according to age group, body fat percentage, regular walking and exercise, and milk consumption compared to the reference value for each classification category. Surprisingly, there were no differences in BMD according to serum 25-OH-D levels. Birth order affected BMD of only whole body except head, but its impact was less than that of lifestyle factors. The mean differences in BMD between daughters and sons in the first and third parental BMD tertiles were statistically significant. Notably, the prevalence ratio of whole body without head BMD being in the low tertile increased eight and ten-folds in adolescent daughters and sons, respectively, when parents were in the low BMD tertile. In specific bone regions, parental BMD had a greater effect on total femur in daughters but in the lumbar spine in sons. In conclusion, parental BMD positively influences BMD in daughters and sons after adjustment for environmental parameters. This suggests that the children from parents with low BMD need to make an extra effort to increase BMD through dietary and lifestyle changes.

Iron deficiency increases blood lead levels in boys and pre-menarche girls surveyed in KNHANES 2010-2011.

INTRODUCTION: We present data from the Korean National Health and Nutritional Examination Survey (KNHANES) 2010-11 on the distribution of blood lead levels, and examine their association with iron deficiency in a representative sample of the adolescent Korean population. METHODS: This study was based on data obtained from KNHANES, in which a rolling sampling design was used to perform a complex, stratified, multistage probability cluster survey of a representative sample of the non-institutionalized civilian population in South Korea. Serum ferritin was categorized into three levels: low (serum ferritin <15.0µg/L), low normal (serum ferritin 15.0-30.0µg/L for girls and 15.0-50.0 for boys), and normal (serum ferritin ≥30.0µg/L for girls and ≥50.0 for boys), and its association with blood lead levels was assessed after adjustment for various demographic and lifestyle factors. RESULTS: The geometric mean (GM) of blood lead in the low serum ferritin group was significantly higher than that in the normal group among boys but not girls. After controlling for covariates, multiple regression analysis showed that blood lead was inversely correlated with serum ferritin levels in boys and pre-menarche girls only. DISCUSSION: The present study shows that iron deficiency increases blood lead levels in a representative sample of the male and pre-menarche female adolescent population, as evaluated in KNHANES. The confounding effect of estrogen on blood lead levels should be considered.

Relationship between bone mineral density and moderate to severe chronic kidney disease among general population in Korea.

Recent studies in Western countries have reported a significant association between glomerular filtration rate (GFR) and bone mineral density (BMD) in the absence of dialysis among the general population. However, there have been few studies regarding renal function and BMD among Korean or Asian subjects with moderate to severe (stage 3 or 4) chronic kidney disease (MS-CKD). The aim of the present study was to investigate the association between MS-CKD and BMD in the general Korean population. BMD, serum creatinine and other measures were obtained from 3,190 subjects (1,428 males and 1,762 females; the fourth Korean National Health and Nutrition Examination Survey). GFR was estimated using the Cockcroft-Gault formula, with adjustment for body surface area. After adjustment for all variables, multiple regression analysis showed that BMD in the femur neck, total femur and lumbar spine were positively associated with eGFR in both males and females. Additional analysis showed that MS-CKD was also significantly associated with osteoporosis in both males and females (odds ratio [OR] 2.20, 95% confidence interval [CI] 1.15-4.20 in males; and OR 1.96, 95% CI 1.33-2.88 in females). Individuals with MS-CKD may be at higher risk of osteoporosis even among Asians.

Work-related infectious diseases among Korean workers compensated under the Industrial Accident Compensation Insurance Law, 2006-2011.

BACKGROUND: Korea has no surveillance system for work-related infectious disease. However, these diseases are compensated by the Korea Workers' Compensation & Welfare Service (KCOMWEL). OBJECTIVES: To understand the nature and distribution of compensated occupational infectious diseases in Korea. METHODS: We used the KCOMWEL electronic database to analyze compensated cases of work-related occupational infectious disease. We reviewed and confirmed diagnoses excluding denied claims, secondary infections, dermatoid diseases, duplicated cases and those with missing information. We calculated the distribution of work-related infectious disease in Korea by occupation, calendar year, gender, age, and employment duration, as well as the annual compensated claim rates (per million). RESULTS: We included 1,062 compensated cases of work-related infectious disease. The most common was scrub typhus (n = 567, 53.4%), followed by tuberculosis (n = 227, 21.4%), viral hepatitis (n = 55, 5.2%), and viral influenza (n = 53, 5.0%). A sudden increase in scrub typhus was observed in 2009. Unskilled laborers, including short-term contract workers in public sectors, were most commonly affected by these diseases, followed by health care professionals. CONCLUSIONS: Workers employed in forestry care in the public sectors and in hospitals were most vulnerable to infections. Proper surveillance systems to monitor infectious diseases among vulnerable working groups and improved prevention measures are needed.

Analysis of factors associated with the workers' health status using periodic health examination data by size of enterprises.

This study was conducted to determine whether the size of an enterprise can make a difference to workers' health and to examine those factors, which influence workers' health. The subjects of this study included 26,324 workers employed in manufacturing industry who received medical examinations at the Industrial Health Center at Yonsei University in 1995, 1996 and 1997. Medical examination data were used as a measure of health. Each enterprise was classified by size into three categories: Small scale enterprises (SSE) that employ no more than 50 regular employees; middle scale enterprise (MSE) that employ from 50 to 300 regular employees; and large scale enterprise (LSE) that employ more than 300 regular employees. Health conditions, according to the size of the enterprise, were determined by comparing prevalence rates, and direct standardization methods were used based upon the Korean population, as a standard population, in order to adjust for differences in population structure. 1. The findings of the medical examinations showed that, the prevalence rate in SSEs was higher than in MSEs or LSEs, but that this relationship was reversed after standardizing for sex and age. 2. Logistic regression analysis showed that, although subjects of advanced age, prolonged work history, and male gender had higher risks of disease, the size of the enterprise had no significant effect upon these risks.

Level of silica in the respirable dust inhaled by dental technicians with demonstration of respirable symptoms.

Dental technicians are exposed to various dusts in working laboratories. This study was conducted to measure level of silica in the respirable dust generated from dental fixed prosthodontics manufacturing processes using Fourier Transform Infrared Spectroscopy (FTIR), and to compare their occurrence of respiratory symptoms with that of non-dental hospital workers (control group). Respirable dusts were personally sampled from dental technicians working at dental laboratories in Seoul Korea according to NIOSH Method 0600. Fifty personal samples were obtained during porcelain or polishing process and weighed by a gravimetric method. Concentration of respirable dust was 651 +/- 548 microg/m3 (Mean +/- SD) with highest concentration of 2,874 microg/m3 during the porcelain process and 725 +/- 414 microg/m3 with highest concentration of 1,764 microg/m3 during the polishing process. Concentration of silica was 6.51 +/- 6.07 microg/m3 with 18.85 microg/m3 highest and 14.88 +/- 11.21 microg/m3 with 50.98 microg/m3 highest for the porcelain and polishing process, respectively. Level of silica contents in the dust was 0.81% and 1.66% for the porcelain and polishing process, respectively. The level of silica contents and silica concentration were significantly different between the two processes. Comparing prevalence of respiratory symptoms between non-smoking seventeen dental technicians and thirty-five control workers, wheezing and rhinorrhea were significantly more manifested in the dental technicians than the controls. Total frequency of respiratory symptoms was also significantly higher in the dental technicians than the controls.

The Effects of Injury and Accidents on Self-rated Depression in Male Municipal Firefighters.

OBJECTIVES: The present study aims to determine the causal relationship between self-rated depression and experiences of injury and accidents in municipal firefighters. METHODS: A panel survey of 186 municipal firefighters measured with depressive symptoms according to the Beck's depression index (BDI) was conducted. The effects of job-related injuries and accidents were evaluated using self-administered questionnaires that were taken once in a 12-month period from 2005 to 2006. Firefighters were classified into the Depression Group or Control Group based on follow-up BDI results with a cutoff level that was set to having "over mild depression." RESULTS: The depression Group was comprised of 17 (9.1%) workers, including 9 firefighters who met had sufficient BDI scores twice in the 2-year test period and newly sufficient BDI scores in the follow-up test. A significantly higher number of subjects in the Depression Group experienced injuries and accidents in the 2-year test period as compared to the Control Group (15.4% vs. 1.5%, p=0.04). Firefighters who experienced injuries and accidents in the 2-year test period had a 7.4 times higher risk of being in the Depression Group than those who had not. As compared to accidents, near-miss accidents revealed stronger risks related to being classified as in the Depression group (adjusted odds ratio [OR] = 4.58, 95% confidence interval [CI] = 1.15-18.18 vs. Adjusted OR = 4.22, 95% CI = 1.08-16.58). CONCLUSION: The above results suggest that we should establish an effective program to promote mental health for groups at high risk for self-rated depression, including persons who have experienced consecutive injuries and accidents as well as near-miss injuries.

Decision tree of occupational lung cancer using classification and regression analysis.

OBJECTIVES: Determining the work-relatedness of lung cancer developed through occupational exposures is very difficult. Aims of the present study are to develop a decision tree of occupational lung cancer. METHODS: 153 cases of lung cancer surveyed by the Occupational Safety and Health Research Institute (OSHRI) from 1992-2007 were included. The target variable was whether the case was approved as work-related lung cancer, and independent variables were age, sex, pack-years of smoking, histological type, type of industry, latency, working period and exposure material in the workplace. The Classification and Regression Test (CART) model was used in searching for predictors of occupational lung cancer. RESULTS: In the CART model, the best predictor was exposure to known lung carcinogens. The second best predictor was 8.6 years or higher latency and the third best predictor was smoking history of less than 11.25 pack-years. The CART model must be used sparingly in deciding the work-relatedness of lung cancer because it is not absolute. CONCLUSION: We found that exposure to lung carcinogens, latency and smoking history were predictive factors of approval for occupational lung cancer. Further studies for work-relatedness of occupational disease are needed.

[Lifestyle and metabolic syndrome among male workers in an electronics research and development company].

OBJECTIVES: The objectives of this study were to determine the relationship between lifestyle-implementation and metabolic syndrome in an electronics research and development company, and to provide a foundation for health providers of health management programs for setting priorities. METHODS: From July 1 to July 16, 2008 we carried out a descriptive cross-sectional survey. Consecutive workers of one R & D company in Seoul, Korea (N=2,079) were enrolled in study. A checklist for lifestyle (from the National Health Insurance Corporation) consisted of questions regarding diet, drinking, smoking and exercise. After the survey, researchers obtained data from health profiles for metabolic syndrome(waist-circumference, triglycerides, HDL cholesterol, blood pressure and fasting blood sugar level). Lifestyle was recorded as good or not good. Statistical analysis of metabolic syndrome and the lifestyle of subjects was done using multiple logistic regression analysis. RESULTS: The prevalence of metabolic syndrome in our study gropu was 13.3% (N=277). After adjustment for age, the adjusted odds ratios (odds ratio, 95% confidence intervals) for metabolic syndrome increased in proportion to the number of bad habits: two (1.72, 1.23-2.44), three (2.47, 1.73-3.56), and four (3.63, 2.03-6.34). Relative to subjects eating both vegetables and meat', the OR for 'meat' eaters was 1.66 (1.18-2.31). Compared with 'non-smokers and ever-smoker', the OR for 'current-smoker' was 1.62 (1.25-2.10). Compared with 'Healthy drinker', the OR for 'unhealthy drinker' was 1.38 (1.05-1.83). CONCLUSIONS: Poor lifestyle was associated with an increased likelihood of metabolic syndrome. These findings suggest that lifestyle-based occupational health interventions for young employees should include a specific diet, smoking cessation, and healthy-drinking programs.