Associations between household incense burning and delayed motor development among preterm infants modified by gestational age and maternal educational status.

BACKGROUND: Household incense burning is a common ritual behavior in the Asia-Pacific region but has been associated with inferior developmental outcomes in term infants. We aimed to examine these associations among preterm infants. METHODS: Information from 1190 mother-infant pairs during 6- and 18-month follow-up to the Taiwan Birth Cohort Study was examined for associations between household incense burning exposure and infant neurodevelopmental milestone achievement using multivariable Cox proportional hazard model with propensity score weighting, along with stratified, sensitivity, and decomposition analysis. RESULTS: Household incense burning exposure was associated with delayed gross motor milestone achievement among all preterm infants according to the Cox model and after propensity score weighting. Meanwhile, associations for delayed development were found in gross motor domain milestones among late preterm infants, while fine motor domain delay was found among other preterm infants. Furthermore, the associations between household incense burning status and gross motor milestone delays were attenuated by the interaction between higher education level and household incense burning exposure status. CONCLUSIONS: Household incense burning exposure was associated with delays, and the motor domains affected differed according to degree of prematurity. These associations were modified by the attenuation upon higher maternal educational status and exposure status interaction.

N-Acetyl-cysteine against noise-induced temporary threshold shift in male workers.

Previous animal studies showed protective effects of antioxidant medicines against noise-induced hearing loss (NIHL). It is unclear whether antioxidants would protect humans from NIHL. We conducted a study to determine whether N-Acetyl-cysteine (NAC) protected men against noise-induced temporary threshold shift (TTS), and whether subgroups with genetic polymorphisms of glutathione S-transferase (GST) T1 and M1 responded to NAC differently. In this prospective, double-blind, crossover study, 53 male workers were randomly assigned to receive either NAC (1200 mg/day, 14 days) during the first period and placebo during the second period, or placebo during the first period and NAC during the second period. Dosing periods were separated by a washout period of 2 weeks. The hearing threshold changes were determined before and after each dosing period. Pre-shift hearing threshold for high frequencies was 19.1 dB. Daily exposure to noise ranged from 88.4 to 89.4 dB. The noise levels of different frequencies ranged from 80.0 to 89.4 dB with a peak-value at 4 kHz. NAC significantly reduced TTS (p = 0.03). When the participants were grouped by GST M1/T1 genotypes, the NAC effect was only significant among workers with null genotypes in both GSTM1 and GSTT1 (p = 0.004). NAC may prevent noise-induced TTS among occupationally noise-exposed men. The protective effect of NAC was more prominent in subjects with both GSTM1-null and GSTT1-null genotypes. (clinicaltrials.gov Identifier: NCT00552786).

Traffic-related air pollution, climate, and prevalence of eczema in Taiwanese school children.

The prevalence of childhood eczema is increasing in many countries. Epidemiological studies, however, say little of its association to outdoor air pollution and climate factors. We conducted a nationwide survey of middle-school students in Taiwan from 1995 to 1996. The 12-month prevalence of eczema was compared with air monitoring station data of temperature, relative humidity, and criteria air pollutants. A total of 317,926 children attended schools located within 2 km of 55 stations. Prevalence rates of recurrent eczema were 2.4 and 2.3% in boys and girls, respectively, with prevalence rates of flexural eczema 1.7% in both sexes. After adjustment for possible confounders, flexural eczema was found to be associated with traffic-related air pollutants, including nitrogen oxides and carbon monoxide. Recurrent eczema was associated with traffic-related air pollution only in girls. There were no associations for the highest monthly means of temperature, whereas the annual means and the lowest monthly means of temperature were negatively related to flexural eczema, but only in girls. The lowest monthly mean relative humidity was positively related to eczema. The results suggest that air pollution and climatic factors, which showed stronger associations in girls than boys, may affect the prevalence of childhood eczema.

Human PCDD/PCDF levels near a pentachlorophenol contamination site in Tainan, Taiwan.

A pentachlorophenol (PCP) manufacturing plant in southern Taiwan discontinued production in 1989. The site of the abandoned plant was heavily contaminated by PCDD/PCDFs, impurities formed in the PCP production process. Serum samples collected from 27 residents living near the deserted plant were evaluated to determine whether this contamination had associated serum levels of PCDD/PCDFs in local residents. The average level of 17 tested congeners ranged from 556 to 5240 pg/g lipid (mean, 1670 pg/g lipid). The corresponding 2,3,7,8-TCDD toxicity equivalent quotient values calculated by international toxicity equivalent factors (I-TEFs) and those recommended by WHO (WHO-TEFs) were 47.2 pg I-TEQ/g lipid and 53.4 pg WHO-TEQ/g lipid, respectively. Levels in other parts of Taiwan typically range from 15 to 20 pg WHO-TEQ/g lipid; therefore, it is likely that the heavily contaminated plant site caused these unusually high serum levels. The average PCDD/PCDF levels of 29 fish-tissue and nine soil samples collected from the sea reservoir surrounding the abandoned PCP plant were also abnormally high: 8630 pg/g lipid (985 pg WHO-TEQ/g lipid) and 606000 pg/g-sample (922 pg WHO-TEQ/g-sample), respectively. Factor analysis indicated that the congener pattern of human serum samples collected from residents living near the abandoned PCP plant different from samples collected from other areas in Taiwan without known PCDD/PCDF pollution. Similar results were observed for the fish tissue and soil samples. The current study may have discovered a "hot spot" for elevated dioxin human exposure in Taiwan. The preliminary finding has raised a public health concern in the inspected area and requires further investigations to clarify the nature of the contamination and potential impact on the local environment and human health.

In utero exposure to dioxins and polychlorinated biphenyls and its relations to thyroid function and growth hormone in newborns.

The aim of this study is to examine the association between transplacental exposure to dioxins/polychlorinated biphenyls (PCBs) and thyroid and growth hormones in newborns. We recruited 118 pregnant women, between 25 and 34 years of age, at the obstetric clinic. Personal data collected included reproductive and medical histories and physical factors. Clinicians gathered placental and umbilical cord serum upon delivery and carefully scored the 118 newborns, making both structural and functional assessments. We analyzed placentas for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans and 12 dioxin-like PCB congeners with the World Health Organization-defined toxic equivalent factors, and six indicator PCBs by high-resolution gas chromatography and high-resolution mass spectrometry. We analyzed thyroid and growth hormones from cord serum using radioimmunoassay. Insulin-like growth factor (IGF)-1, IGF-binding globulin-3, and thyroxine x thyroid-stimulating hormone (T4 x TSH) were significantly associated with increased placental weight and Quetelet index (in kilograms per square meter; correlation coefficient r = 0.2-0.3; p < 0.05). Multivariate analyses showed independently and significantly decreased free T4 (FT4) x TSH with increasing non-ortho PCBs (r = -0.2; p < 0.05). We suggest that significant FT4 feedback alterations to the hypothalamus result from in utero exposure to non-ortho PCBs. Considering the vast existence of bioaccumulated dioxins and PCBs and the resultant body burden in modern society, we suggest routine screening of both thyroid hormone levels and thyroid function in newborns.

Yucheng: health effects of prenatal exposure to polychlorinated biphenyls and dibenzofurans.

Yucheng ("oil-disease") victims were Taiwanese people exposed to polychlorinated biphenyls (PCBs) and their heat-degradation products, mainly polychlorinated dibenzofurans (PCDFs), from the ingestion of contaminated rice oil in 1978-1979. Serial studies in Yucheng offspring born between 1978 and 1992 are summarized. Children of the exposed women were born with retarded growth, with dysmorphic physical findings, and, during development, with delayed cognitive development, increased otitis media, and more behavioral problems than unexposed children. Recently, examination of the reproductive system has suggested that prenatal exposure exerts late effects on semen parameters in young men after puberty. Results of the investigation in Yucheng children will provide important information about the human health effects and toxicology of PCB/PCDF exposure. Prenatal exposure to these environmental chemicals causes the fetus to be sensitive to the toxic effects of persistent organic pollutants.

Prevalence of musculoskeletal disorder among workers in Taiwan: a nationwide study.

Musculoskeletal disorder (MSD) is a common problem among workers. In spite of the numerous reports on MSD in various specific groups of workers, few data on the prevalence in the general working population are available except for back pain. We analyzed the information collected through a nationwide survey in Taiwan in 1994 to estimate the prevalence of MSD by age, gender, and education level and identify high-risk industries. In the survey, a standard questionnaire was distributed to a representative sample of 22,475 non-self-employed workers in Taiwan. National estimates were obtained by applying a weight to each participant. Among the sampled workers, 18,942 (84.3%) participated, and 37.0% (standard error=0.4%) had MSD. Female workers had a significantly higher overall prevalence than male workers (39.5% vs. 35.2%, p<0.05). Education and age also had significant associations with MSD (p<0.001 in both genders). "Lower back and waist" were the most frequently affected body parts (18.3% among males and 19.7% among females), but the prevalence of MSDs of the neck, shoulders, hands and wrists were also above 10%. The top ten high-risk major industries for MSD of various body parts for each gender were identified, and some industries, including "Basic Metal Industries" and "Buildings Construction," were among the top ten for multiple body parts. Our study showed that MSDs of body parts other than the back are also prevalent, especially in the neck, shoulders, hands and wrists. We also identified high-risk industries for further research and intervention.