Association between Cesarean section delivery and increased risk of childhood Kawasaki disease.

AIM: Cesarean section delivery is associated with microbiota disruption and immuno-dysregulation during childhood, but the association with Kawasaki disease remains uncertain. We aimed to evaluate the association between Cesarean section and Kawasaki disease. METHODS: We examined the association between Kawasaki disease between six and eighteen months and Cesarean section within a birth cohort of 15,796 mother-infant pairs in Taiwan. The associations were assessed with Poisson regression in the study population, in the 1:2 propensity score-matched subpopulation, and compared with febrile convulsion, trauma and accidents during the same interval as negative control outcomes. RESULTS: Cesarean section was found to increase the risk of Kawasaki disease among overall population (adjusted relative risk [aRR]: 2.22, 95 % confidence interval (CI): 1.14-4.34) and the matched subpopulation (aRR: 2.29, 95 % CI: 1.14-4.68 in PS-matched subpopulation). Meanwhile, there was no association between Cesarean section and the clinic visits for febrile convulsion, trauma and accidents. CONCLUSION: In conclusion, this study identified a potential association between Cesarean section delivery and a higher risk of Kawasaki disease during six-to eighteen months of the prospective birth cohort in Taiwan.

Associations Between Infant Developmental Delays and Secondhand Smoke Exposure Modified by Maternal Prepregnancy Overweight and Obesity Status.

INTRODUCTION: Secondhand smoke exposure during pregnancy has long been associated with adverse health outcomes in children, but only a few studies have examined its effect modifiers. In this study, we applied effect modification analysis for maternal prepregnancy weight status on detrimental neurodevelopmental effect of secondhand smoke exposure during pregnancy and infancy in a nationwide representative population. AIMS AND METHODS: Term singleton mother-infant pairs with nonsmoking mothers were included for main analysis (N = 15 987) from the Taiwan Birth Cohort Study (TBCS), and were further matched with propensity score (n = 5434). We extracted secondhand smoke exposure during pregnancy and infancy, and eight neurodevelopmental milestones from the responses in the baseline visit at 6 months, and 18-month follow-up of TBCS. The associations between secondhand smoke exposure and neurodevelopmental achievement were analyzed with multivariable logistic regression and Cox model. Propensity score weighting and matching were applied for high-versus-low analysis, and relative excess risk due to interaction were used to estimate effect modification. RESULTS: Higher secondhand smoke exposure was associated with increased likelihood of delayed milestone achievement across gross motor, fine motor, language-related, and social-related domains. The associations in fine motor domains remained observable in propensity score-weighted and -matched models. We identified additive interaction with self-reported maternal overweight and obesity status before pregnancy in milestone development for walking with support, scribbling, and waving goodbye. CONCLUSIONS: Secondhand smoke exposure during pregnancy and infancy were associated with delayed neurodevelopmental milestone achievement at 18 months, and the associations were modified by maternal prepregnancy overweight and obesity status. IMPLICATIONS: The study results suggested the association between maternal secondhand smoke exposure during pregnancy and infancy and delayed fine motor and language-related milestone achievement at 18 months in multivariable, propensity score weighting, and matching populations. The results of positive effect modifications for maternal prepregnancy overweight and obesity status suggested the importance of concurrent interventions on smoke-free environment and maternal health during pregnancy.

Health related quality of life and polychlorinated biphenyls and dibenzofurans exposure: 30 years follow-up of Yucheng cohort.

BACKGROUND: Quality of life (QOL) can be affected by diseases, disasters, and exposure events to environmental factors. However, whether health-related QOL (HRQOL) might be adversely affected by exposure to dioxin-like chemicals 30 years ago is unknown. METHODS: We studied people who were poisoned to polychlorinated biphenyls (PCBs) and dibebenzofurans (PCDFs) due to ingestion of contaminated rice oil in 1979 in central Taiwan, and were called Yucheng (oil-disease in Chinese) people. In 2008, we conducted a survey in 1305 exposed people by mailed questionnaire, which included HRQOL by World Health Organization (WHO) quality of life-BREF (WHOQOL-BREF) Taiwanese version. A total of 240 Yucheng subjects aged 18-65 years satisfactorily completed the Questionnaire. For comparison, we obtained information from the database of 2001 National Health Survey conducted by the National Health Research Institute and Bureau of Health Promotion, Department of Health, Taiwan. Data from age-, sex-, and county-matched background individuals were extracted using 1:3 match. HRQOL among Yucheng people with/without skin manifestation and unexposed referents were compared, while adjusting for other factors by multiple regression analyzes. RESULTS: The Yucheng people had significantly reduced scores in the physical, psychological, social, and environmental domains as compared to the referents. Those with skin manifestations were more severely affected than those with no skin manifestations, suggesting a dose-related effect on QOL in exposed people. CONCLUSION: We show for the very first time that poisoning due to persistent organic pollutants PCBs and PCDFs can affect QOL 30 years after the exposure, especially among those most severely poisoned.

Haemophilus influenzae type b combination vaccines and atopic disorders: a prospective cohort study.

BACKGROUND/PURPOSE: Epidemiologic evidence for an association between vaccinations and atopy development is inconsistent. We evaluated the influence of Haemophilus influenzae type b (Hib) combination vaccines in 6-month-old infants on the prevalence of atopic disorders in 18-month-old children. METHODS: We used multistage, stratified systematic sampling to recruit 24,200 mother-newborn pairs from the Taiwan national birth registration in 2005. Vaccination status was ascertained through official vaccine cards, while risk factors for atopic disorders were gathered by questionnaires at 6 months of age. Information about development of atopic dermatitis (AD) and recurrent wheezing was collected at 18 months of age. The relationship between atopic disorders and Hib combination vaccines, diphtheria-pertussis-tetanus-Hib and oral poliomyelitis vaccines (DPT-Hib&OPV) and DPT-Hib-inactivated poliomyelitis vaccines (DPT-Hib-IPV), were estimated by multiple logistic regression. RESULTS: A total of 19,968 children completed the follow-up and participated in the study. AD was noted in 1584 (7.9%) infants while recurrent wheezing was found in 1220 (6.1%) infants. The adjusted odds ratios (ORs) (95% CI) for the development of AD in the DPT-Hib&OPV and DPT-Hib-IPV vaccination groups were given as 1.38 (1.15-1.65) and 1.49 (1.29-1.72), compared to those without Hib vaccination (DTP&OPV vaccination). However, the association between DPT-Hib&OPV and DPT-Hib-IPV vaccinations and recurrent wheezing failed to reach statistical significance. CONCLUSION: There is a potential risk for AD after receiving Hib combination vaccines. Hib vaccination is important to the public health, and therefore the observation requires further investigations.

Assaults against nurses of general and psychiatric hospitals in Taiwan.

PURPOSE: Nurses are at risk of occupational assaults. However, the incidence and effects have not been documented among nurses in Taiwan. We aimed to study the incidence of assaults and their effects, including quality of life and job-related stress among nurses. METHODS: A cross-sectional study was conducted to understand the incidence of work-related assaults in nurses. Job content questionnaire was used to determine the job control, psychological demands at work, and workplace support in these nurses. Quality of life was assessed by short form-36 (SF-36). RESULTS: A total of 842 nurses satisfactorily completed the questionnaire, including 375 from general hospitals and 467 from psychiatric hospitals. A total of 237 (28.1%) reported to have experienced physical and/or verbal assaults in past 6 months. Experiences of sexual assault or verbal abuse were risk factors for feeling threatened by potential attacks. Nurses who felt threatened by potential attacked scored lower in general health, mental health, and vitality by SF-36, and had higher psychological demands at work, lower job control, and lower workplace support. CONCLUSION: We conclude that nurses in general and psychiatric hospitals had high risk of assaults. Worksite assaults caused nurses to feel threatened, and such an effect was likely to cause increased job stress and decreased quality of life.

Indoor environmental risk factors and seasonal variation of childhood asthma.

Seasonality of asthma may result from varying exposures. This cross-sectional study was designed to examine the relationship between indoor environmental factors and seasonal childhood asthma. Study subjects were participants from the International Study of Asthma and Allergies in Childhood (ISAAC) in 2004, a population-based surveillance, which included school children aged 6-15 yr in south Taiwan. Cases included 1725 children who experienced asthma symptoms in the past 12 months and the references consisted of 19,646 children who reportedly have no asthma history. By using a moving average and principal component analysis, asthmatic children were grouped into four asthma subtypes: winter, spring, summer/fall, and perennial. Multivariate logistic regression was used to evaluate the effect of indoor environmental factors on seasonality of childhood asthma. For all asthma prevalence, a peak occurred in the winter and a nadir appeared in summer. Contributing factors of asthma for children, regardless of seasonality, included younger age, parental atopy, maternal smoking during pregnancy, breast feeding, and perceived air pollution. After adjusted for salient risk factors, water damage was significantly associated with all subtypes of asthma. Presence of cockroaches was related to the summer/fall asthma (adjusted odds ratio [aOR] = 1.65, 95% confidence interval [CI] = 1.12-2.55). Visible mold on the walls was associated with an increased occurrence of winter and spring asthma (aOR = 1.53, 95% CI = 1.26-1.85 and aOR = 1.34, 95% CI = 1.10-1.62, respectively). Passive smoking was shown to be related to spring and summer/fall asthma. Water damage is a possible risk for childhood asthma year-round. Cockroaches and visible mold on the walls may play essential roles for seasonality of childhood asthma in Taiwan. Plausible mechanisms and allergic effects should be further determined. Elimination of these allergens is necessary to help prevent the development of asthma.

Association between maternal shift work and infant neurodevelopmental outcomes: results from the Taiwan Birth Cohort Study with propensity-score-matching analysis.

BACKGROUND: Maternal shift work is associated with preterm delivery, small-for-gestational-age new-borns, childhood obesity and future behavioural problems. However, the adverse effects on and interactions of maternal shift work with infant neurodevelopment remain uncertain. Therefore, we examined the associations between maternal-shift-work status and infant neurodevelopmental parameters. METHODS: The Taiwan Birth Cohort Study is a nationwide birth cohort study following representatively sampled mother-infant pairs in 2005. The participants' development and exposure conditions were assessed by home interviews with structured questionnaires at 6 and 18 months of age. Propensity scores were calculated with predefined covariates for 1:1 matching. Multivariate conditional logistic regression and the Cox proportional-hazards model were used to examine the association between maternal-shift-work status and infant neurodevelopmental-milestone-achievement status. RESULTS: In this study, 5637 term singletons were included, with 2098 cases selected in the propensity-score-matched subpopulation. Persistent maternal shift work was associated with increased risks of delays in gross-motor neurodevelopmental milestones [aOR = 1.36, 95% confidence interval (CI) = 1.06-1.76 for walking steadily], fine-motor neurodevelopmental milestones (aOR = 1.39, 95% CI = 1.07-1.80 for scribbling) and social neurodevelopmental milestones (aOR = 1.35, 95% CI = 1.03-1.76 for coming when called upon). Moreover, delayed gross-motor and social development were identified in the propensity-score-matched sub-cohort. CONCLUSIONS: This study shows negative associations between maternal shift work and delayed neurodevelopmental-milestone achievement in the gross-motor, fine-motor and social domains at 18 months. Future research is necessary to elucidate the possible underlying mechanisms and long-term health effects.

Neurocognitive changes among elderly exposed to PCBs/PCDFs in Taiwan.

BACKGROUND: In 1979 approximately 2,000 people were exposed to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) due to ingestion of contaminated cooking oil in Taiwan. Although a previous study has shown delayed developmental milestones and poorer neurocognitive functioning in children born to exposed mothers, it is unclear whether neurocognitive functioning was impaired in people who were directly exposed to the PCBs and PDCFs. OBJECTIVE: The objective of this study was to compare neurocognitive functioning in people exposed to PCBs and PCDFs with that of unexposed sex- and age-matched neighbors. METHODS: We conducted a retrospective cohort study among exposed and unexposed subjects > or =60 years of age using prospective outcome measurements. We evaluated neurocognitive tests including cognition, memory modalities, learning, motor and sensory function, mood, and daily activity. RESULTS: In total, 162 (59%) exposed and 151 (55%) reference subjects completed this study. In exposed men, all test results were similar to the reference group; however, exposed women had reduced functioning in attention and digit span (ADS), visual memory span (VMS), and verbal memory recalls (VMR), especially learning ability. We also found a borderline reduction in the Mini-Mental State Examination. The digit symbol, motor, sensory, depression (determined by the Geriatric Depression Scale-Short Form), and activity of daily life were not different between the exposed and reference groups. A significant dose-response relationship was found for VMR, ADS, and VMS. CONCLUSION: Our study showed dose-dependent neurocognitive deficits in certain aspects of attention, visual memory, and learning ability in women previously exposed to PCBs and PCDFs, but not in exposed men.

Exposure to a mixture of polychlorinated biphenyls and polychlorinated dibenzofurans resulted in a prolonged time to pregnancy in women.

BACKGROUND: Polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs), and dibenzodioxins (PCDDs) may affect the female reproductive system in animals and humans. In 1978-1979, a mass poisoning occurred in central Taiwan due to PCB/PCDF-contaminated cooking oil; this incident was called Yucheng ("oil disease" in Chinese). OBJECTIVE: The purpose of our study was to determine whether PCB/PCDF exposure affected fertility in exposed women. METHODS: After the event, we followed the exposed individuals and a reference group who were sex-, age-, and community-matched. In 2003, we obtained fertility histories from Yucheng and reference women by telephone interview. We used Kaplan-Meier survival curves and multivariable Cox regression to compare time to pregnancy (TTP) between Yucheng and reference women, and we performed multiple logistic regression to determine whether PCB/PCDF exposure caused infertility. RESULTS: In total, 412 women responded, with a median TTP of 4 months in Yucheng women and 3 months in reference women (p = 0.019). After adjusting for confounders by Cox regression, we found a fecundability ratio of 0.90 [95% confidence interval (CI), 0.80-1.00] for Yucheng women. Among the 408 women who had non-contraceptive sexual activity for > 12 months, 19.7% of Yucheng women and 9.7% of reference women did not become pregnant (i.e., they were infertile). After we adjusted for confounders by logistic regression, the infertility odds ratio was 2.34 (95% CI, 1.23-4.59) for Yucheng women compared with the reference group. CONCLUSIONS: We found prolonged TTP and reduced fertility among women previously exposed to PCBs/PCDFs. Because of the limited sample size and the relatively small decrease in the fertility rate, these effects require cautious interpretation and further investigation for confirmation.

Effect of gestational smoke exposure on atopic dermatitis in the offspring.

The adverse impact of smoking on respiratory diseases and birth outcomes in children is well-known. However, the influence of smoke exposure including environmental tobacco smoke (ETS) and maternal smoking during pregnancy on atopic dermatitis (AD) is not clear. The purpose of this study was to evaluate the effect of gestational smoke exposure on the development of AD in the offspring on the basis of the maternal and cord blood cotinine. We recruited 261 mother and newborn pairs in 2004. Cord blood and information on perinatal factors of children were gathered at birth. At 2 yr of age, information about development of AD and environmental exposures were collected. We compared AD with non-AD children for the concentration of cotinine in cord and maternal blood measured by high performance liquid chromatography-mass spectrometry. Multiple logistic regressions were performed to estimate the relationship of cotinine levels and AD. About 150 mother and child pairs completed the follow-up study and specimen collection with 38 (25.3%) children developing AD. Two (1.3%) out of 150 mothers smoked during pregnancy, while 38 (25.3%) mothers reported having ETS exposure. Cotinine levels in cord blood and maternal blood were highly correlated (r = 0.71, p < 0.001). The risk of AD was found to increase with maternal and cord blood cotinine levels in a dose-response manner (p for trend = 0.01). Children exposed to high levels (>75th percentile) had a significantly increased risk of AD. Smoke exposure during pregnancy might increase the risk of AD in children. Avoidance of prenatal smoke exposure may be warranted for early prevention.

Reduced expression of von Hippel-Lindau gene in subjects exposed to polychlorinated biphenyls and dibenzofurans.

Polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) are ubiquitous pollutants found in the environment and human tissues. A cohort in Taiwan has undergone follow-up for 24 years after exposure to high levels of PCBs and PCDFs. The incidence of chloracne, hyperkeratosis, and abnormal nail was increased among exposed people. We conducted a study to identify the genes whose expressions were affected by such exposure. A cDNA microarray system consisting of 908 genes was used for pooled serum samples from non-smoking men exposed to PCBs and PCDFs (n=15) and their matched referents (n=15) in triplicate. After adjusting for background and housekeeping genes, genes with different expressions between the exposure and reference groups were determined by both regression and cluster analysis, and further confirmed by real-time RT-PCR. The tumor suppressor gene von Hippel-Lindau (VHL) was found to be down-regulated in the microarray analysis. VHL gene expression levels were also found to be positively associated with age, shown by real-time RT-PCR. Upon age adjustment, VHL gene expression was reduced in Yucheng ("oil disease") subjects as compared to referents. Among Yucheng people, those with abnormal nails had lower VHL expressions than those without abnormal nails. These findings provide new insights into the potential role of VHL in health conditions associated with PCB and PCDF exposures.

2-Naphthol Levels and Allergic Disorders in Children.

BACKGROUND: The measurement of polycyclic aromatic hydrocarbons (PAH) in ambient air is quite difficult to perform. Using urine biomarkers of PAH such as 2-naphthol is one approach to this problem. This study explored the association between urine 2-naphthol levels and allergic diseases. The associations between 2-naphthol levels and oxidative stress biomarkers for the possible disease pathogenesis were also investigated. METHOD: A total of 453 kindergarten children from the (Childhood Environment and Allergic Diseases Study) CEAS cohort with urine samples were recruited. Urine 2-naphthol levels were measured by high-performance liquid chromatography mass spectrometry (HPLC-MS/MS) and markers of oxidative stress (8OHdG) were measured by enzyme-linked immunosorbent assays (ELISA). Information on environmental risk factors and allergic diseases were also collected. The association between 2-naphthol levels, 8OHdG levels, IgE, and allergic diseases were evaluated by multivariate linear regression and logistic regression. RESULTS: Levels of 2-naphthol were positively correlated with 8OHdG levels. A one ln-unit increase in the 2-naphthol level was positively associated to 8OHdG levels (per ln-unit: ß = 100.61, p < 0.001). When dividing 2-naphthol levels into quartiles, asthma was significantly associated with 2-naphthol levels at a concentration of >1.60 ng/mL (adjusted OR: 3.14, 95% CI 1.34⁻7.35). CONCLUSION: Urine 2-naphthol levels are associated with markers of oxidative stress and the risk of allergic diseases in young children.

Will daytime occupational noise exposures induce nighttime sleep disturbance?

BACKGROUND: Nighttime environmental noise affects sleep quality. However, the effects of daytime occupational noise remain unclear. METHODS: A quasi-experiment of 48 participants who had been employed for at least six months in two hospital cafeterias. The participants were randomly designated to be assessed on high- and low-noise workdays for 8 h or low- and high-noise workdays, separated by a washout period of 14 days. Subsequently, pure tone audiometry, autonomic nervous system (ANS) function tests, serum cortisol tests, and polysomnography were conducted. RESULTS: For the 40 participants in the study, the 8-h time-weighted average of personal noise exposed on high- and low-noise workdays was 76.8 dBA (standard deviation, SD: 6.2) and 61.0 dBA (SD: 7.1), respectively. Participants with higher personal noise exposure during the day were found to have a lower percentage of slow wave sleep (percent change of mean value: -1.287%; 95% CI: -2.602%, -0.037%) and lower sleep efficiency (-0.267%; 95% CI: -0.525%, -0.008%). In addition, after work, personal noise exposure was revealed to be related to increased serum cortisol levels (1.698%; 95% CI: 0.887%, 2.528%), and sympathetic activity as measured by low frequency/high frequency (3.000%; 95% CI: 1.294%, 4.706%) and blood pressures by cold pressor test (systolic: 5.163%; 95% CI: 2.780%, 7.537%) (diastolic: 3.109%; 95% CI: 1.604%, 4.614%). CONCLUSIONS: Daytime occupational noise exposure had sustained effects on nighttime sleep quality, specifically on slow wave sleep and sleep efficiency. These disturbances could be partially explained by post-shift elevated cortisol and ANS activity. The psychosocial and metabolic consequences of poorer sleep quality induced by occupational noise exposure warrant further investigation.

Household incense burning and infant gross motor development: Results from the Taiwan Birth Cohort Study.

BACKGROUND: Air pollution from biomass burning were associated with neurodevelopmental deceleration, but limited studies concerned about the effect of indoor biomass burning. Incense burning is a common household ritual practice in Taiwan, while past studies mainly focused on birth weight and allergic disease. OBJECTIVES: We aimed to find the association between incense burning exposure and children's neurodevelopment. METHODS: In Taiwan Birth Cohort Study (TBCS), a nationwide representative birth cohort study, children were assessed upon home interview with structured questionnaires upon six and eighteen months old. Multivariate logistic and Cox proportional hazard regression adjusting confounding factors were applied to explore the odds ratio (OR) and hazard ratio (HR) between household incense burning exposure and caregiver-reported neurodevelopment milestones. RESULTS: In this study, 15,310 term singletons were included, and household incense burning was associated with delay in gross motor neurodevelopment milestone, such as walking with support (Occasional incense burning: OR = 1.26, 95% confidence interval (CI): 1.08 to 1.47, HR = 1.07, 95% CI: 1.03 to 1.11; persistent incense burning: OR = 1.44, 95% CI: 1.22 to 1.69, HR = 1.11, 95% CI: 1.07 to 1.16) and walking steadily (Occasional incense burning: OR = 1.14, 95% CI: 0.98 to 1.32, HR = 1.07, 95% CI: 1.03 to 1.11, persistent incense burning: OR = 1.24, 95% CI: 1.06 to 1.45, HR = 1.09, 95% CI: 1.04 to 1.13). CONCLUSIONS: Our study suggested household incense burning exposure was associated with delay in gross motor neurodevelopmental milestones. Further research is warranted to elucidate the possible mechanism and causal relationship.

Increased liver and lupus mortalities in 24-year follow-up of the Taiwanese people highly exposed to polychlorinated biphenyls and dibenzofurans.

BACKGROUND: A follow-up study was designed to compare the 24-year overall and disease-specific mortality in Yucheng people who were highly exposed to polychlorinated biphenyls/dibenzofurans (PCBs/PCDFs) to that in the background population in Taiwan. In 1979, the Yucheng (oil-disease in Chinese) incident occurred in central Taiwan involving approximately 2000 victims due to ingestion of rice oil contaminated with PCBs/PCDFs. Long-term follow-up of these people has been continued for 24 years. METHODS: Standardized mortality ratios were calculated using the Taiwan population as comparison group. Overall and disease-specific mortality was compared between Yucheng and background populations. RESULTS: Mortality from chronic liver disease and cirrhoses was increased in the Yucheng men, but not in women, in the early period after exposure. Cancer mortality was not increased in the Yucheng population up to 24 years after exposure. SLE in females was highly increased in the later period after PCB/PCDF exposure. Mortality from disease in any other organ system was not significantly different between Yucheng and background populations. CONCLUSIONS: The study provided a long-term mortality picture after the Taiwanese PCB/PCDF exposure incident. In addition to re-confirming the increase in liver mortality, we found high mortality of SLE among exposed population. This finding highlights the importance of further investigating the immunological effects associated with PCB/PCDF exposure.

A comparison of PCDD/PCDFs exposure in infants via formula milk or breast milk feeding.

Food is the major source for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) accumulation in human body. In infant period, breast milk and formula milk are the major food sources. Congener-specific analyses of 17 PCDD/PCDFs were performed on 10 brands of formula milk samples which were milk-based and 37 breast milk samples collected from women living in southern Taiwan. The levels of 17 PCDD/PCDFs in 10 formula milk samples ranged from 0.468 to 0.962 pg WHO-TEQ/g lipid, with a mean value of 0.713+/-0.163 pg WHO-TEQ/g lipid. For the 37 breast milk samples, their PCDD/PCDF levels were 14.7+/-9.36 pg WHO-TEQ/g lipid, with a range between 4.21 and 52.8 pg WHO-TEQ/g lipid. At 12th month of age for infants, average daily intakes (ADI) of PCDD/PCDFs were 2.1 pg WHO-TEQ/kg/day for the formula-feeding infants, and 13 pg WHO-TEQ/kg/day for the breast-feeding infants. The present data may provide useful information for risk-benefit evaluation of formula- and breast-feeding.

Prevalence of hearing impairment in an adult population in Southern Taiwan.

The objective of this study was to estimate the prevalence of hearing impairment in a representative adult population in southern Taiwan and compare the results to those of similar studies in other countries. A stratified systematic cluster sample of 1140 residents, aged > or =20 years, of Tainan City was studied from 2001 to 2003. The test battery included otoscopy, pure-tone audiometry, and a questionnaire covering relevant personal, occupational, and family history. The hearing threshold level (HTL) was defined as the better ear pure-tone average (BPTA) (i.e. the average of hearing thresholds at frequencies 500, 1000, 2000, and 4000 Hz). The prevalence of hearing impairment was 21.4% (95% confidence interval: 19.3-23.7%) at BPTA > or =25 dB HTL. Middle ear disease was a significant risk factor for hearing impairment in addition to age and gender. The overall prevalence of hearing impairment may be higher in Taiwan (17.1%) than in western populations (11.5%), but differences in the definition of hearing impairment severity and variation in sex distribution among studies may account for this higher prevalence.

Genetic polymorphisms in CYP1A1 and GSTM1 predispose humans to PCBs/PCDFs-induced skin lesions.

INTRODUCTION: Polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs) are ubiquitous persistent pollutants in humans. Whether people with different genotypes are with different susceptibility to these chemicals are unknown. In a group of people highly exposed to PCBs/PCDFs, we tested the hypothesis that genotypic polymorphisms affected susceptibility for development of skin manifestations. METHODS: In 1979, approximately 2000 people in central Taiwan ingested cooking oil contaminated with PCBs/PCDFs. Skin disorder such as chloracne, abnormal nail, hyperkeratosis and skin allergy were found in PCBs/PCDFs exposed group. We recruited exposed and community background exposure subjects for blood testing and telephone-interview. Single nucleotide polymorphisms, AhR Arg554Lys, CYP1A1 Ile462Val, CYP1A1 T6235C, and GSTM1/T1 deletion, were determined. Occurrence of skin manifestations was compared among people with different genotypes while stratified by PCB exposure levels by logistic regression. RESULTS: Data on exposure, medical history, and genotypes were obtained from 393 exposed and 181 background exposure groups. Skin manifestations including chloracne, allergy, abnormal nail, and hyperkeratosis were more prevalent in exposed people in a dose-related manner. Among highly exposed individuals, combined CYP1A1-MspI mutant genotype and GSTM1-null genotype were associated with increased risk of chloracne (odds ratio 2.8, 95% confidence interval 1.1-7.6). Among intermediately exposed individuals, GSTM1 null genotype was associated with skin allergy. AhR Arg554Lys genotype and GSTT1 null genotype were not related to susceptibility to skin manifestations in PCB/PCDF-exposed population. CONCLUSION: CYP1A1 and GSTM1 genotypic polymorphisms might be related to the susceptibility to PCB/PCDF-induced skin manifestations.

Genetic and environmental predictors for pediatric atopic dermatitis.

BACKGROUND: The purpose of this study was to evaluate the influence of genetic and various environmental factors for atopic dermatitis (AD) occurring in the first 18 months of life. METHODS: We used the multistage stratified systematic sampling to recruit 2,048 mother-child pairs from the Taiwan National Birth Registry in 2003. Information on family history of atopy and environmental risk factors for AD of children were gathered by questionnaires at 18 months of age. Multiple logistic regressions were performed to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) for risk factors of the AD after adjusting for potential confounders. RESULTS: AD was noted in 147/1618 (9.08%) of the children. We found maternal history of AD, maternal grandparents' history of AD, higher family income, and higher maternal education level increased the risk of pediatric AD. The adjusted ORs and their 95% CIs were 4.10 (1.27-13.25), 4.56 (1.39-15.00), 1.66 (1.00-2.77), and 1.71 (1.56-6.97), respectively. However, duration of breast feeding did not alter the risk estimates of AD. CONCLUSIONS: AD may be inherited preferentially through the maternal line. Prevention of special environmental exposures is urgently needed for children with maternal history of AD.