C K Ho

Chung Shan Medical University, 臺中市, Taiwan, Taiwan

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Publications (31)105.07 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Previous research has suggested that heavy metals may be ototoxic in humans, and further, that a reversal of this toxicity may occur when the trace element selenium is present, through formation of metals selenide complexes. This study investigates the relationship between hearing thresholds and blood concentrations of four elements (selenium, lead, manganese, and arsenic) in factory workers, Taiwan. We conducted a hospital-based case-control study with 294 individuals who received the periodic occupational health examination in the Kaohsiung Medical University Hospital. All control subjects (n=173) had normal hearing. Case subjects (n=121) had average hearing threshold over 25 decibels (dB). In all individuals, blood concentrations of lead (Pb), manganese (Mn), arsenic (As), and selenium (Se) were determined by an ICP-MS and standard methods. Possible confounding factors were collected by a questionnaire and medical history reviews. Relationships were analyzed by multiple linear regressions and mixed model. Geometric means of Pb, Mn, As, and Se were determined for case subjects (107.2, 5.5, 17.8, and 229.1 microg/L) and controls (38.9, 5.4, 15.5, and 234.4 microg/L). In our regression models, age, lead and selenium concentrations (logarithmic transformed) were associated significantly with hearing thresholds. In addition, we found that the selenium was inversely associated with hearing thresholds, and may be an antagonist to lead ototoxicty. The present study demonstrated a dose-response relationship between blood lead and hearing thresholds, after adjusting other potential confounders in multiple regressions. In addition, we found that selenium may be a protection element on auditory function. However, additional studies will be needed to clarify the mechanisms of lead toxicity and selenium on the hearing function in molecular and genetic levels.
    Science of The Total Environment 11/2007; 387(1-3):79-85. DOI:10.1016/j.scitotenv.2007.07.032 · 4.10 Impact Factor
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    ABSTRACT: BACKGROUND: Both active cigarette smoking and human papillomavirus (HPV) infection are known risk factors for cervical intraepithelial neoplasm (CIN). The association between second-hand smoke (SHS) and CIN has not been conclusively determined. We conducted a community-based case-control study to estimate the relationship between SHS and CIN. METHODS: Potential study subjects were selected through Pap smear screening in Kaohsiung County, Taiwan. A total of 171 subjects with either their first case of inflammation (benign epithelial lesion) or > or = CIN1 by biopsy confirmation were assigned to a case group; 513 normal subjects with negative findings by Pap smears or biopsies were assigned to a control group. RESULTS: Non-smoking women exposed to more than 20 pack-years of cigarette smoke had a significantly greater risk of developing > or = CIN2 than unexposed non-smokers (adjusted OR=7.2, 95% CI=2.5-20.6). Among the women without HPV infections, the greater the severity of disease found in the groups (normal, inflammation, CIN1, to > or = CIN2), the more likely it was for the women to be exposed to SHS, a significant increasing trend (p=0.037). CONCLUSIONS: In addition to HPV infection and active cigarette smoking, exposure to SHS is a major risk factor for CIN among Taiwanese women.
  • Epidemiology 11/2006; 17. DOI:10.1097/00001648-200611001-00909 · 6.18 Impact Factor
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    ABSTRACT: OBJECTIVES: Our aim is to analyze the association between polycyclic aromatic hydrocarbon (PAH) exposure and the temporal change of urinary 1-hydroxypyrene (1-OHP). METHODS: Two personal air samples, eight spot urine samples, and questionnaires were used to collect PAH exposure, urinary 1-OHP, demographic data, and environmental pollutants. RESULTS: Topside-oven workers had significantly higher levels of PAH exposure and 1-OHP than side-oven workers. Urinary 1-OHP was a biomarker for PAH exposure. In topside-oven workers, the trend of 1-OHP increased sharply and reached the top in the sixth day after work and declined dramatically on days off. In side-oven workers, such a trend was not found, and those who smoked showed a slight increase in urinary 1-OHP levels on days off. CONCLUSIONS: We suggest that the pattern of temporal change of urinary 1-OHP levels is different between topside-oven and side-oven workers.
    Epidemiology 11/2006; 48(9):930-6. DOI:10.1097/00001648-200611001-00477 · 6.18 Impact Factor
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    ABSTRACT: Human papillomavirus (HPV) infection is a high-risk factor for cervical intraepithelial neoplasm (CIN) but the association between the quantitative HPV DNA load and the severity of CIN remains controversial. We conducted a community study to investigate the correlation between the two. Potential study subjects were selected through Pap smear screening in Kaohsiung County, Taiwan. Ninety-one subjects with either their first case of inflammation or > or =CIN1 by biopsy confirmation were assigned to a case group; 175 normal subjects with negative findings by Pap smears or biopsies were assigned to a control group. Cervical HPV load was detected with Hybrid Capture II assay for high-risk HPV infection, with nested PCR for high- and low-risk HPV infection, and with type-specific PCR for HPV type 16 (HPV-16). Individuals with positive high-risk HPV infection had an increased risk of developing CIN. Compared with HPV-negative subjects, the odds ratios were 32.2 [95% confidence interval (95% CI), 10.4-99.5] for subjects with CIN1, 37.2 (95% CI, 7.4-187.6) for subjects with CIN2, and 68.3 (95% CI, 14.1-328.5) for subjects with > or =CIN3 after adjusting for other confounding factors. The similar trend was also found among the HPV-16-negative individuals. In addition, high-risk HPV DNA load levels were highly correlated with the different grades of CINs in the overall population (Spearman's correlation coefficient r = 0.67, P < 0.0001, n = 266) and the HPV-16-negative population (Spearman's correlation coefficient r = 0.58, P < 0.0001, n = 234). We concluded that high-risk HPV infection, irrespective of HPV-16 infection, was highly and positively associated with the development of CIN.
    Cancer Epidemiology Biomarkers & Prevention 01/2005; 14(11 Pt 1):2544-9. DOI:10.1158/1055-9965.EPI-05-0240 · 4.32 Impact Factor
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    ABSTRACT: The dietary calcium supplement has been suggested to children and pregnant women for prevention of lead toxicity, because of lead-calcium interaction. Lead workers were supplied free milk in Taiwan; however, part of workers did not drink milk due to lactose intolerance. The goal of this study is to evaluate the effects of milk-intake on the peripheral nervous system in workers with long-term lead exposure. We measured 181 workers' current perception thresholds (CPT) as neurological outcomes. The outcome variables were then correlated to the subject's milk intake, blood lead levels, and index of long-term lead exposure that was calculated by the subject's serial blood lead data in a period of working duration. The potential confounders, including age, gender, body height, smoking and alcohol consumption, were also collected and analyzed in multiple regressions. 23 workers who reported never or rarely drinking milk, which meant that they have suffered from diarrhea or abdomen discomfort after drinking milk since childhood, had higher blood lead parameters but not statistically significant, and higher thresholds in sensory nerve tests, especially, statistically significance on 5 and 250 Hz of hand CPTs, which represent C fiber and A-delta fiber. In multiple regression models with control of potential confounders, significant protective effects of milk intake were found on reducing hand CPTs, but not on foot CPTs. Our study, using measurement of sensory nerve CPTs, revealed that drinking milk (two bottles a day, about 700 g per day) might have an effect to protect lead peripheral neurotoxicity. The detail biochemical mechanisms need further investigations. However, reduction of occupational lead exposure is the essential way to protect lead neuropathy. The authors did not emphasize that offers of milk to workers could be instead of occupational hygiene efforts. Furthermore, lead workers with lactose intolerance might be more susceptible, and need more industrial hygiene interventions.
    NeuroToxicology 12/2004; 25(6):941-9. DOI:10.1016/j.neuro.2004.04.003 · 3.05 Impact Factor
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    ABSTRACT: BACKGROUND: Although most needlestick/sharps injuries (NSIs/SIs) research focuses on health care workers (HCWs), students in hospital internships are also at risk. Investigations that examined NSIsS/SIs in student populations generally studied medical rather than nursing students (NSs). In 1999, approximately 17,000 Taiwanese nursing graduates were exposed to the hazard of NSIs/SIs. We examined the frequency and mechanism of NSIs/SIs among vocational school NSs in southern Taiwan. METHODS: Between July and December of 1999, within 1 week after the NSs completed their internship training, one of the researchers, who was a teacher in this vocational school, asked them to fill out questionnaires. RESULTS: Five hundred twenty-seven of 550 (92.6%) questionnaires were considered valid. Two hundred sixty-four of 527 (50.1%) responders sustained one or more NSIs/SIs. Ninety-six of 527 (18.2%) responders suffered contaminated NSIs/SIs. The average number of NSIs/SIs per student was 8.0 times/year (4.9 times/student/year for NSIs and 3.1 times/student/year for SIs). NSIs/SIs rates for NSs in 10-week and 4-week internships were significantly different ( P = .039): 53.3% versus 43.7%, respectively. The NSIs/SIs frequencies were influenced by length of internship: 7.3 times/student/year in 10-week internship and 11.7 times/student/year in 4-week internship. Logistic regression analysis indicated that length of internship rotation was statistically significant with respect to contaminated NSIs/SIs (OR = 1.682; 95% CI: 1.005-2.81; P = .048). CONCLUSIONS: The NSIs/SIs frequencies of NSs were higher than those for HCWs. We found that frequency of NSIs/SIs for vocational school NSs is above average. Whether the young age of these NSs put them at greater risk for NSIs/SIs warrants further inquiry.
    American Journal of Infection Control 12/2004; 32(8-8):431-5. DOI:10.1016/S0196655304004523 · 2.33 Impact Factor
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    ABSTRACT: Investigations of Vitamin D Receptor Polymorphism Affecting Workers' Susceptibility to Lead: Hung-Yi CHUANG, et al. Department of Occupational Medicine, Kaohsiung Medical University Hospital, Kaohislung City, Taiwan-Gene polymorphism is an important factor that affects human susceptibility to toxins. For example, previous studies suggested that the ALAD genotype is an important factor affecting workers' susceptibility to lead toxic effects, including hemopoietic and nervous system. But we have had few researches in Taiwan, though there are thousands of workers involved in lead-related industries. On the other hand, although it is well known that lead deposits in the bone mineral component and interacts with calcium, vitamin D receptor may therefore be an important factor in the metabolism of lead. Some studies suggested that different vitamin D receptor genotypes have various kinds of receptor activity. The goal of this study was to investigate the polymorphism affecting workers' susceptibility to lead. Three allelic variants of the VDR gene were defined by means of the polymerase chain reaction (PCR) and three restriction enzymes (Apal, Bsml, and Taql). We determined the relationships of different VDR genotypes (AA, Aa, aa, BB, Bb, bb, TT, Tt, and tt) to blood lead and the index of cumulative blood lead levels (ICL). Altogether we analyzed 544 workers' VDR genotypes (Bsml, Taql, and Apal) and compared to their blood lead levels and ICL in the VDR genotypes. The results showed that workers had higher blood lead levels and ICL in the Apa I- aa genotypes, but this is not statistically significant when adjusted for potential confounding factors. Other characteristics, such as exposure status, smoking and alcohol drinking, were significantly associated with ICL and time-weighted ICL. Regression analyses suggested that exposure status and personal habits (smoking and alcohol drinking) are still the major effects on blood lead parameters for lead workers rather than genotypes. In conclusion, VDR genotypes did not significantly affect the long term blood lead parameters after adjustment for all factors, but industrial hygiene improvement, including engineering control and health education, are the most important ways to protect workers' health.
    Journal of Occupational Health 07/2004; 46(4):316-322. DOI:10.1539/joh.46.316 · 1.10 Impact Factor
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    ABSTRACT: Air pollution has been associated with daily mortality in numerous studies over the past decade. However most of these studies were conducted in the United States and Europe with relatively few done in Asia. In the current study, the association between ambient air pollution and daily mortality in Taipei, Taiwan's largest city which has a subtropical climate was undertaken, for the period 1994-1998 using a case-crossover analysis. This design is an alternative to Poisson time series regression for studying the short-term adverse health effects of air pollution. The air pollutants examined included particulate matter (PM(10)), sulfur dioxide (SO(2)), ozone (O(3)), nitrogen dioxide (NO(2)), and carbon monoxide (CO). The largest observed effect, which was without statistical significance, was seen for NO(2) and CO levels on deaths due to respiratory diseases (ORs=1.013 and 1.014, respectively). The well established link between air pollution levels and daily mortality may not be as strong in cities in subtropical areas, although other factors such as differences in pollutant mix or the underlying health of the population may explain the lack of a strong association in this study. Further studies of this type in cities with varying climates and cultures are needed.
    Environment International 06/2004; 30(4-4):519-23. DOI:10.1016/j.envint.2003.10.006 · 5.66 Impact Factor
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    ABSTRACT: The petrochemical and petroleum industries are two of the main sources of industrial air pollution in Taiwan. Data used in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to oil refinery plants. The prevalence of delivery of preterm birth infants was significantly higher in mothers living near the oil refinery plants than in control mothers in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.14 (95% CI=1.01-1.28) for delivery of preterm infants for mothers living near oil refinery plants. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancies.
    Environment International 05/2004; 30(3-3):337-42. DOI:10.1016/S0160-4120(03)00180-6 · 5.66 Impact Factor
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    ABSTRACT: Traffic emissions are a major source of air pollution in urban areas. The results of recent studies have suggested that air pollution may be related to adverse pregnancy outcomes such as low birth weight and preterm delivery. The authors investigated the association between traffic-related air pollution and preterm deliveries. The study group included all first-parity singleton live births that occurred during 1992-1997 to women who lived in a zone along the Zhong-Shan Freeway in Taiwan (N = 6,251). The zone was defined as areas 1,500-m wide on either side of the freeway; it was located in the San-Ming, Nan-Tzu, Chienchen, and Linya wards-all of which are residential areas in East Kaohsiung. The prevalence of deliveries of preterm birth infants was significantly higher among mothers who lived within 500 m of the freeway than among mothers who resided 500-1,500 m from the freeway. In their analysis, the authors controlled for several confounders (e.g., maternal age, season, marital status, maternal education, infant gender). The adjusted odds ratio was 1.30 (95% confidence interval = 1.03, 1.65) for delivery of preterm infants born to mothers who lived within 500 m of the freeway. Such data provide additional support for the hypothesis that air pollution can affect the outcome of pregnancy.
    Archives of Environmental Health An International Journal 10/2003; 58(10-10):649-54. DOI:10.3200/AEOH.58.10.649-654
  • Epidemiology 09/2003; 14. DOI:10.1097/00001648-200309001-00228 · 6.18 Impact Factor
  • 15th Conference of the; 09/2003
  • 15th Conference of the; 09/2003
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    ABSTRACT: The well water in Lanyang Basin, which is located in the northeastern portion of Taiwan island, was found to have high levels of arsenic ranging from undetectable levels (<0.15 ppb) to 3.59 ppm. We performed a study to compare the risk of adverse pregnancy outcomes (preterm delivery and birthweight) between an area with historic high well water arsenic levels (arsenic-exposed area (AE)) and a comparison area with no historic evidence of arsenic water contamination (non-arsenic-exposed area (NAE)). The mean birth weight in the AEs and NAEs were 3132.6 and 3162.6 g, respectively. Babies born in AEs were on average 30 g lighter than those born in NAEs. AEs had a higher rate of preterm delivery than NAEs (3.74% vs 3.43%). The results of this study suggest that, after adjustment for potential confounders, arsenic exposure from drinking well water was associated, although not significantly, with the risk of preterm delivery, with an odds ratio of 1.10 (0.91-1.33). The estimated reduction in birth weight was 29.05 g (95% CI=13.55-44.55). The findings from this investigation provide evidence for a potential role for arsenic exposure through drinking water in increasing the risk of low birthweight.
    Environmental Research 01/2003; 91(1-1):29-34. DOI:10.1016/S0013-9351(02)00015-4 · 3.95 Impact Factor
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    ABSTRACT: The Portland cement industry is the main source of particulate air pollution in Kaohsiung city. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to Portland cement plants. The prevalence of delivery of preterm birth infants was significantly higher in mothers living within 0-2 km of a Portland cement plant than in mothers living within 2-4 km. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.30 (95% CI=1.09-1.54) for the delivery of preterm infants for mothers living close to the Portland cement plants, chosen at the start to be from 0 to 2 km. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy.
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    ABSTRACT: Over the past 20 years lead has been proven to exert an influence on the intelligence of children. Especially for children exposed to environmental lead, average blood lead was often lower than the officially recognized intoxication level. Because Kaohsiung is an industrial area in Taiwan and lead exposure is an important environmental issue, we attempted to ascertain the extent to which environmental lead influences the achievement of primary school children. We randomly selected 934 children from 32 primary schools in 11 districts of Kaohsiung City. Blood lead levels of the children were checked, and they were administered a questionnaire about their family information. Scores of several courses were used in this study on the relationship between a child's blood lead and his or her academic performance (Ranking with his or her classmates), including Chinese (reading and writing short Chinese articles), Mathematics, History and Society, and Natural Science. Multiple regression models were done with adjustments for the confounding effects of their parents' socioeconomic levels. The mean (SD) of 934 blood lead level was 5.50 (1.86) microg/dL. Spearman's coefficient showed that class rankings in Chinese, Mathematics, Natural Science, and History and Society were all strongly associated with blood lead levels (P<0.01). The multiple regression models revealed that blood lead level exerts a stronger influence on children's language ability (Chinese) than on their ability to calculate (Mathematics). Our results suggest that environmental lead exposure adversely affects a child's academic achievement, making a direct link between exposure to lead and academic attainment.
    Environmental Research 01/2002; 89(1):12-8. DOI:10.1006/enrs.2002.4342 · 3.95 Impact Factor
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    ABSTRACT: Among 104 cases of squamous-cell oesophageal carcinoma patients and 277 controls in Taiwan, after adjusting for cigarette smoking, alcohol consumption, and other confounders, we found that subjects who chewed from 1 to 495 betel-year and more than 495 betel-years (about 20 betel quid per day for 20 years) had 3.6-fold (95% Cl = 1.3–10.1) and 9.2-fold risk (95% Cl = 1.8–46.7), respectively, of developing oesophageal cancer, compared to those who did not chew betel. © 2001 Cancer Research Campaign http://www.bjcancer.com
    British Journal of Cancer 10/2001; 85(5):658-60. DOI:10.1054/bjoc.2001.1927 · 4.82 Impact Factor
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    ABSTRACT: The aims of this study were to examine some of the factors that influence tibia lead concentrations, tibia lead x-ray fluorescence measurement uncertainty and blood lead concentrations, and to compare tibia lead concentrations in Taiwanese lead workers to those observed in lead workers from other countries. A pilot evaluation of 43 adult lead workers who underwent measurements of tibia lead and blood lead concentrations. Mean and maximum tibia lead concentrations were 54 microg of Pb per g of bone mineral(microg/g) and 193 microg/g, respectively. Mean and maximum blood lead concentrations were 44 microg/dl and 92 microg/dl, respectively. Past occupational control of lead exposure in Taiwan, ROC, did not prevent these workers from accumulating tibia lead concentrations greater than those in similar workers elsewhere in the world.
    American Journal of Industrial Medicine 09/2001; 40(2):127-32. · 1.59 Impact Factor

Publication Stats

587 Citations
105.07 Total Impact Points


  • 2007
    • Chung Shan Medical University
      臺中市, Taiwan, Taiwan
  • 2004–2007
    • Kaohsiung Medical University
      • Department of Public Health
      Kao-hsiung-shih, Kaohsiung, Taiwan
  • 2006
    • Cheng Shiu University
      Kao-hsiung-shih, Kaohsiung, Taiwan
  • 1999–2004
    • Institute of Occupational Safety and Health, Taiwan
      T’ai-pei, Taipei, Taiwan
  • 2002
    • Yuan's General Hospital
      Kao-hsiung-shih, Kaohsiung, Taiwan
  • 1997
    • Kaohsiung Municipal Ta-Tung Hospital, Taiwan
      Kao-hsiung-shih, Kaohsiung, Taiwan