Association between secondhand smoke and peripheral arterial disease: a meta-analysis of cross-sectional studies.

PURPOSE: The association between secondhand smoke (SHS) and peripheral arterial disease (PAD) was inconsistent and the studies were relatively scarce, hence, we conducted a meta-analysis of the association between SHS and PAD. MATERIALS AND METHODS: We systematically searched three electronic databases (PubMed, EMBASE, and Web of Science), and calculated the pooled prevalence risk ratio (RR) and estimated standard error by random effect model from the meta-analysis. Furthermore, we performed a subgroup meta-analysis according to the location of SHS exposure. RESULTS: We initially identified 502 articles from the electronic database, and 6 articles, cross-sectional data from 4 cross-sectional studies and 2 prospective cohort studies, were included in the meta-analysis. Among these six articles, two studies showed a significant correlation between SHS exposure and PAD, whereas no study showed a negative correlation between SHS exposure and PAD. In the meta-analysis, pooled prevalence showed a significant association between SHS exposure and PAD (RR = 1.23; 95% confidence interval [CI] 1.08-1.41; z = 3.02, p = 0.003). In the subgroup analysis based on location of SHS exposure, the prevalence RR of PAD at home was 1.30 (95% CI 1.14-1.49, Z-3.99, p < 0.0001). The prevalence RR in the subgroup of SHS exposure at work was not significant (RR = 0.89; 95% CI 0.55-1.44; z = 0.48, p = 0.63). CONCLUSION: Exposure to SHS was significantly and positively associated with PAD. Moreover, we found a significant association between exposure to SHS and PAD at home, but the association was not significant at work.

Toxic Metals Increase Serum Tumor Necrosis Factor-α Levels, Modified by Essential Elements and Different Types of Tumor Necrosis Factor-α Promoter Single-nucleotide Polymorphisms.

BACKGROUND: Lead (Pb), cadmium (Cd), and arsenic (As) could cause health issues through oxidative stress that is indicated in the elevated tumor necrosis factor-alpha (TNF-α). However, some of the essential elements-selenium (Se), zinc (Zn), cobalt (Co), and copper (Cu)-are cofactors or structural components of antioxidant enzymes. It is suggested that single-nucleotide polymorphisms (SNPs) in the TNF-α gene have different TNF-α responses. This study aims to evaluate the effect of serum TNF-α levels through the interactions between toxic metals and essential elements and how the interactions between the toxic metals and TNF-α SNPs (-1031 T > C, -863 C > A, -857 C > T, -308 G > A, -238 G > A) influence serum TNF-α levels. METHODS: Blood samples were collected from 455 workers who carried out annual health examinations and multielements determined by inductively coupled plasma mass spectrometry (ICP-MS). TNF-α levels were detected by enzyme-linked immunosorbent assay (ELISA). TNF-α promoter SNPs were analyzed by specific primer probes using real-time polymerase chain reaction (PCR) methods. RESULTS: Increasing blood Pb, Cd, and As levels were associated with elevated TNF-α levels. The interaction between Pb and Cu decreased TNF-α levels and so did the interaction between Cd and Se. In the interaction between Pb and SNPs, individuals with AA/AG (-308 G > A) and AA/AG (-238 G > A) had higher serum TNF-α levels. However, lower TNF-α levels were noted in those individuals with AA/CA (-863 C > A). In the interaction between As and SNPs, workers with AA/AG (-238 G > A) had synergic effect with As and induced higher serum TNF-α levels. CONCLUSIONS: Blood Cu and Se were antagonists of toxic metals (Pb, As, and Cd) through lower serum TNF-α levels. Variant types of TNF-α SNPs (-308 G > A, -238 G > A) and wild type of -863 CC would be more susceptible to toxic metals.

Dichotic multiple-frequency auditory steady-state responses in evaluating the hearing thresholds of occupational noise-exposed workers.

An objective, fast, and reasonably accurate assessment test that allows for easy interpretation of the responses of the hearing thresholds at all frequencies of a conventional audiogram is needed to resolve the medicolegal aspects of an occupational hearing injury. This study evaluated the use of dichotic multiple-frequency auditory steady-state responses (Mf-ASSR) to predict the hearing thresholds in workers exposed to high levels of noise. The study sample included 34 workers with noise-induced hearing impairment. Thresholds of pure-tone audiometry (PTA) and Mf-ASSRs at four frequencies were assessed. The differences and correlations between the thresholds of Mf-ASSRs and PTA were determined. The results showed that, on average, Mf-ASSR curves corresponded well with the thresholds of the PTA contours averaged across subjects. The Mf-ASSRs were 20±8dB, 16±9dB, 12±9dB, and 11±12dB above the thresholds of the PTA for 500Hz, 1,000Hz, 2,000Hz, and 4,000Hz, respectively. The thresholds of the PTA and the Mf-ASSRs were significantly correlated (r=0.77-0.89). We found that the measurement of Mf-ASSRs is easy and potentially time saving, provides a response at all dichotic multiple frequencies of the conventional audiogram, reduces variability in the interpretation of the responses, and correlates well with the behavioral hearing thresholds in subjects with occupational noise-induced hearing impairment. Mf-ASSR can be a valuable aid in the adjustment of compensation cases.

Predicting hearing thresholds and occupational hearing loss with multiple-frequency auditory steady-state responses.

OBJECTIVE: An objective investigation is needed to verify the existence and severity of hearing impairments resulting from work-related, noise-induced hearing loss in arbitration of medicolegal aspects. We investigated the accuracy of multiple-frequency auditory steady-state responses (Mf-ASSRs) between subjects with sensorineural hearing loss (SNHL) with and without occupational noise exposure. DESIGN: Cross-sectional study. SETTING: Tertiary referral medical centre. METHODS: Pure-tone audiometry and Mf-ASSRs were recorded in 88 subjects (34 patients had occupational noise-induced hearing loss [NIHL], 36 patients had SNHL without noise exposure, and 18 volunteers were normal controls). MAIN OUTCOME MEASURES: Inter- and intragroup comparisons were made. A predicting equation was derived using multiple linear regression analysis. RESULTS: ASSRs and pure-tone thresholds (PTTs) showed a strong correlation for all subjects (r = .77 ≈ .94). The relationship is demonstrated by the equationThe differences between the ASSR and PTT were significantly higher for the NIHL group than for the subjects with non-noise-induced SNHL (p < .001). CONCLUSIONS: Mf-ASSR is a promising tool for objectively evaluating hearing thresholds. Predictive value may be lower in subjects with occupational hearing loss. Regardless of carrier frequencies, the severity of hearing loss affects the steady-state response. Moreover, the ASSR may assist in detecting noise-induced injury of the auditory pathway. A multiple linear regression equation to accurately predict thresholds was shown that takes into consideration all effect factors.

A population-based, case-control study of green tea consumption and leukemia risk in southwestern Taiwan.

OBJECTIVE: This study investigated the association between green tea consumption and leukemia. METHODS: A total of 252 cases (90.3% response) and 637 controls (53.4% response) were enrolled. Controls were matched for cases on age and gender. Information was collected on participants' living habits, including tea consumption. Green tea was used as a standard to estimate the total amount of individual catechin consumption. We stratified individual consumption of catechins into four levels. Conditional logistic regression models were fit to subjects aged 0-15 and 16-29 years to evaluate separate associations between leukemia and catechin consumption. RESULTS: A significant inverse association between green tea consumption and leukemia risk was found in individuals aged 16-29 years, whereas no significant association was found in the younger age groups. For the older group with higher amounts of tea consumption (>550 units of catechins), the adjusted odds ratio (OR) compared with the group without tea consumption was 0.47 [95% confidence interval (CI) = 0.23-0.97]. After we adjusted for smoking status and medical irradiation exposure, the overall OR for all participants was 0.49 (95% CI = 0.27-0.91), indicating an inverse relation between large amounts of catechins and leukemia. CONCLUSION: Drinking sufficient amounts of tea, especially green tea, which contains more catechins than oolong tea and black tea, may reduce the risk of leukemia.

The H-Wave((R)) Device Induces NODependent Augmented Microcirculation and Angiogenesis, Providing Both Analgesia and Tissue Healing in Sports Injuries.

UNLABELLED: The hypothesis that the H-Wave(R) device (Electronic Waveform Lab, Inc., Huntington Beach, CA), a small-diameter fiber stimulator, is a paradigm shift of electrotherapeutic treatment of pain associated with human neuropathies and sports injuries is based on a number of its properties. The primary effect of H-Wave(R) device stimulation (HWDS) is the stimulation of "red-slow-twitch" skeletal muscle fibers. The authors propose, based on the unique waveform, that the H-Wave(R) device specifically and directly stimulates the small smooth muscle fibers within the lymphatic vessels ultimately leading to fluid shifts and reduced edema. In unpublished rat studies, it has been observed that HWDS induces protein clearance. The H-Wave(R) device was designed to stimulate an ultra low frequency (1-2 Hz), low tension, nontetanizing, and nonfatiguing contraction, which closely mimics voluntary or natural muscle contractions. The H-Wave(R) device can stimulate small fibers due in part to its exponentially decaying waveform and constant current generator activity. The main advantage of these technologies over currently applied electrical stimulators (eg, transcutaneous electrical nerve stimulator [TENS], interferential [IF], neuromuscular electrical stimulation [NMES], high-volt galvanic, etc.) is that H-Wave\'s(R) small fiber contraction does not trigger an activation of the motor nerves of the large white muscle fibers or the sensory delta and C pain nerve fibers, thus eliminating the negative and painful effects of tetanizing fatigue, which reduces transcapillary fluid shifts. Another function of the H-Wave(R) device is an anesthetic effect on pain conditions, unlike a TENS unit which in the short term activates a hypersensory overload effect (gate theory) to stop pain signals from reaching the thalamic region of the brain. When the H-Wave(R) device is used at high frequency (60 Hz), it acts intrinsically on the nerve to deactivate the sodium pump within the nerve fiber, leading to a long-lasting anesthetic/analgesic effect due to an accumulative postsynaptic depression. Moreover, HWDS produces a nitric oxide (NO)-dependent enhancement of microcirculation and angiogenesis in rats. Thus, the authors hypothesize that because of these innate properties of the H-Wave(R) device, it may provide a paradigm shift for the treatment of both short- and long-term inflammatory conditions associated with pain due to sports injuries. A recent meta-analysis found a moderate-to-strong effect of the H-Wave(R) device in providing pain relief, reducing the requirement for pain medication, and increasing functionality. The most robust effect was observed for improved functionality, suggesting that the H-Wave(R) device may facilitate a quicker return to the field. KEYWORDS: H-Wave(R) device; sportsmedicine, nitric oxide-dependent blood flow; analgesia; angiogenesis.

A case-control study on the relationship of hearing function and blood concentrations of lead, manganese, arsenic, and selenium.

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.

Residential exposure to petrochemicals and the risk of leukemia: using geographic information system tools to estimate individual-level residential exposure.

The authors conducted a population-based, case-control study in Kaohsiung, southern Taiwan, Republic of China, to investigate the association between residential petrochemical exposure and leukemia risk among subjects 29 years of age and younger. Between November 1997 and June 2003, 171 cases and 410 controls matched for age and sex were recruited. Since assessment of petrochemical impacts depends on accurate exposure estimates, the authors developed a procedure using geographic information system tools to assign subjects' exposure. The resulting individual-level exposure estimates (the exposure opportunity score) are an integrated exposure measure that accounts for subjects' mobility, length of stay at each residence, distance to petrochemical plant(s), monthly prevailing wind direction, and multiple petrochemical pollution sources. Different conditional logistic regression models were fitted for subjects aged 0-19 and 20-29 years to evaluate separately childhood versus adulthood leukemia. No overall association was observed for the younger age group. However, residential petrochemical exposure was a significant risk factor for leukemia for the older age group. For one unit of increase in the log-transformed exposure opportunity score, the adjusted odds ratio was 1.54 (95 percent confidence interval: 1.14, 2.09). This study illustrates the utility of geographic information system tools for providing refined exposure estimates for residential exposure to petrochemical pollution.

The influence of milk intake on the lead toxicity to the sensory nervous system in lead workers.

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.

Increased risk of preterm delivery among people living near the three oil refineries in Taiwan.

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.

Suspended onion particles and potential corneal injury in onion harvesters.

The authors suspected that suspended onion particles contributed to corneal ulcers in onion harvesters in southern Taiwan. In the present study, the authors used manikins to study suspended onion particles in fields in an effort to simulate typical conditions experienced by onion harvesters. An animal eye-exposure simulation study was also performed by the authors, who impacted suspended soil grains or onion particles onto the corneas of guinea pigs via aerosol generated from the Palas dispersion nozzle. The average size of 25.9 pm for suspended particles collected during the digging of onions was the largest one of those for various harvesting activities. Some onion skin flakes were found in samples obtained from gathering and packing activities; the typical flake size was approximately 3.5 x 2.5 mm2. The results of the animal study indicated that the size of soil grains has a demonstrable effect on the severity of corneal injury (p = .009). With respect to onion skin flakes, wind velocity was also associated significantly with the occurrence of corneal injury (p = .0004). A wind velocity threshold of 7 m/sec is recommended for the maintenance of safety, and if the wind speed exceeds this threshold level, workers should not engage in harvesting activities. Furthermore, use of appropriately designed goggles is necessary for the protection of onion harvesters who work in high-wind conditions.

Fungi genus and concentration in the air of onion fields and their opportunistic action related to mycotic keratitis.

The authors determined fungi concentrations and genera from onion fields located in monsoon and nonmonsoon areas of Taiwan, as well as concentrations from a county housing location, which served as the comparison site. The authors explored the relationship(s) among onion harvesting, monsoon characteristics, airborne fungal levels, and mycotic eye infection. Airborne fungal levels in the onion field in the nonmonsoon area were the highest, followed by decreasing levels in the monsoon area and control sites, regardless of the sampling periods. The geometric mean of airborne fungal concentrations was the highest during onion harvesting. Cladosporium was the most dominant fungus during pre- and postharvest seasons, whereas Aspergillus, Fusraium, Acremonium, Alternaria, Penicillium, Monilia, Mycelia, and Rhizopus were increased significantly during harvesting. Although fungal concentrations in monsoon onion fields were lower than concentrations measured in the nonmonsoon area, the invasion of dangerous fungal pathogens following eye trauma by airborne sharp exotics (e.g., onion flakes) dispersed in high wind may account for the increase in corneal ulcer cases that occur in the monsoon area.