Chronic respiratory symptoms among workers at a limestone factory in Zambia

Prevalence and risk factors of chronic respiratory symptoms in public and private school teachers in north-western Ethiopia: results from a multicentre cross-sectional study

OBJECTIVE

This study aimed to investigate the prevalence and risk factors of chronic respiratory symptoms among school teachers in Gondar city, north-western Ethiopia.

DESIGN

A school-based cross-sectional study was conducted from April to May 2019. A self-administered British Medical Research Council Questionnaire was used to assess chronic respiratory symptoms. Data were entered into Epi Info V.7 and Stata V.14 was used for analysis. A multivariable logistic regression analysis was conducted to identify factors associated with chronic respiratory symptoms. The association was determined using adjusted OR (AOR) with a 95% CI at a value of p<0.05.

SETTING

The study was conducted in public and private schools in Gondar city.

PARTICIPANTS

A total of 822 teachers participated in this study.

OUTCOME MEASURES

The primary outcome is the prevalence of chronic respiratory symptoms.

RESULTS

The total response rate was 97.4%. The majority, 532 (64.7%) of the participants, were male. The mean age (±SD) of the respondents was 36.69 (±6.93) years. The total prevalence of chronic respiratory symptoms in the previous 12 months among teachers in Gondar city was found to be 31.14% (95% CI 27.99% to 34.43%). A family history of respiratory problems (AOR=1.90; 95% CI 1.07 to 3.37), an overweight body mass index (AOR=2.57; 95% CI 1.57 to 4.21), exposure to secondhand cigarette smoke at home (AOR=9.85; 95% CI 4.77 to 20.33), use of chalk (AOR=1.97; 95% CI 1.25 to 3.09), and failure to open windows during class (AOR=2.15; 95% CI 1.02 to 4.52) were risk factors for chronic respiratory symptoms.

CONCLUSION

This study concluded that the prevalence of chronic respiratory symptoms was high among teachers. Making a smoking-free zone, avoiding smoking in public places, improving the ventilation conditions of the classrooms and controlling the chalk dust are all necessary actions to take to reduce chronic respiratory symptoms.

Physicochemical characterization of particulate matter in a cement production plant

Employees working in cement production plants are exposed to airborne particulate matter (PM) which may lead to lung function impairments and airway symptoms. The PM consists of raw materials, clinker and additives which vary depending on cement blend. The aim of this work was to characterize the thoracic fraction of PM with regard to size, phase composition and mixing state. Both stationary and personal impactors were used to collect size-fractionated samples in a cement production plant in Norway. Stationary samples were measured with aerosol particle counters and collected with a 13-stage cascade impactor, which were stationed at three locations of the cement production plant: at the raw meal mill, clinker conveyor belt and cement mill. Sioutas cascade impactors, and thoracic and respirable dust samplers were used in parallel for personal sampling. Additionally, particles for electron microscopy were collected with the stationary cascade impactor for size-fractionated single particle characterization. Gravimetric measurements and element compositions of the samples from the stationary impactors show that the PM mass is dominated by calcium-rich particles of size >1 μm. The size distribution results of stationary and personal impactors were similar. Characterization of single particles reveals that limestone is the dominating material in the raw meal mill, whereas clinker and limestone dominate at the clinker conveyor belt and at the cement mill. The element composition of clinker PM did not change with particle size. The PM collected on impactor stages with aerodynamic diameter cut-offs below 0.56 μm was dominated by soot and volatile secondary particles at the three locations. The number of ultrafine particles of the cement related compounds was low. Air concentrations of PM in personal respirable and thoracic samples ranged from 0.14-10 mg m^-3 to 0.37-9.5 mg m^-3, respectively. Considerable local variations exist, both in composition and air concentration of the PM.

Pulmonary functions and associated risk factors among school teachers in a selected Nigerian population

Objective. This study aimed to determine pulmonary functions and associated risk factors among school teachers. Methods. This cross-sectional ex-post facto study included 121 participants (20 males and 101 females). The setting for this study included 11 private schools and eight government schools. Participants were recruited using non-probability sampling techniques. Subjective data were collected using a self-administered asthma questionnaire. A spirometer was used for measuring pulmonary function values and data were analyzed using descriptive statistics and one-way analysis of variance for inferential statistics. The α level was set at 0.05. Results. Age, gender, duration of employment, type of school, school level taught, type of teaching board, working hours per day, previous occupation, usage of carpet and usage of rugs were significantly associated with the forced vital capacity prediction (p = 0.000, 0.010, 0.000, 0.032, 0.013, 0.000, 0.027, 0.000, 0.000 and 0.041, respectively). Also, the forced expiratory volume in 1 s and the peak expiratory flow were statistically different with alcohol consumption (p = 0.015) and place of residence (p = 0.004), respectively. Conclusion. Teachers using chalkboards are at increased risk of developing occupationally related pulmonary impairments. Hence, there is a need to shift from routine chalkboards to whiteboards.

Environmental Health Research in Africa: Important Progress and Promising Opportunities

The World Health Organization in 2016 estimated that over 20% of the global disease burden and deaths were attributed to modifiable environmental factors. However, data clearly characterizing the impact of environmental exposures and health endpoints in African populations is limited. To describe recent progress and identify important research gaps, we reviewed literature on environmental health research in African populations over the last decade, as well as research incorporating both genomic and environmental factors. We queried PubMed for peer-reviewed research articles, reviews, or books examining environmental exposures and health outcomes in human populations in Africa. Searches utilized medical subheading (MeSH) terms for environmental exposure categories listed in the March 2018 US National Report on Human Exposure to Environmental Chemicals, which includes chemicals with worldwide distributions. Our search strategy retrieved 540 relevant publications, with studies evaluating health impacts of ambient air pollution (n=105), indoor air pollution (n = 166), heavy metals (n = 130), pesticides (n = 95), dietary mold (n = 61), indoor mold (n = 9), per- and polyfluoroalkyl substances (PFASs, n = 0), electronic waste (n = 9), environmental phenols (n = 4), flame retardants (n = 8), and phthalates (n = 3), where publications could belong to more than one exposure category. Only 23 publications characterized both environmental and genomic risk factors. Cardiovascular and respiratory health endpoints impacted by air pollution were comparable to observations in other countries. Air pollution exposures unique to Africa and some other resource limited settings were dust and specific occupational exposures. Literature describing harmful health effects of metals, pesticides, and dietary mold represented a context unique to Africa. Studies of exposures to phthalates, PFASs, phenols, and flame retardants were very limited. These results underscore the need for further focus on current and emerging environmental and chemical health risks as well as better integration of genomic and environmental factors in African research studies. Environmental exposures with distinct routes of exposure, unique co-exposures and co-morbidities, combined with the extensive genomic diversity in Africa may lead to the identification of novel mechanisms underlying complex disease and promising potential for translation to global public health.

Comparative cytotoxicity of respirable surface-treated/untreated calcium carbonate rock dust particles in vitro

Calcium carbonate rock dust (RD) is used in mining to reduce the explosivity of aerosolized coal. During the dusting procedures, potential for human exposure occurs, raising health concerns. To improve RD aerosolization, several types of anti-caking surface treatments exist. The aim of the study was to evaluate cytotoxicity of four respirable RD samples: untreated/treated limestone (UL/TL), untreated/treated marble (UM/TM), and crystalline silica (SiO₂) as a positive control in A549 and THP-1 transformed human cell lines. Respirable fractions were generated and collected using FSP10 high flow-rate cyclone samplers. THP-1 cells were differentiated with phorbol-12-myristate-13-acetate (20 ng/ml, 48 h). Cells were exposed to seven different concentrations of RD and SiO₂ (0-0.2 mg/ml). RD caused a slight decrease in viability at 24 or 72 h post-exposure and were able to induce inflammatory cytokine production in A549 cells, however, with considerably less potency than SiO₂. In THP-1 cells at 24 h, there was significant dose-dependent lactate dehydrogenase, inflammatory cytokine and chemokine release. Caspase-1 activity was increased in SiO₂- and, on a lesser scale, in TM- exposed cells. To test if the increased toxicity of TM was uptake-related, THP-1 cells were pretreated with Cytochalasin D (CytD) or Bafilomycin A (BafA), followed by exposure to RD or SiO₂ for 6 h. CytD blocked the uptake and significantly decreased cytotoxicity of all particles, while BafA prevented caspase-1 activation but not cytotoxic effects of TM. Only TM was able to induce an inflammatory response in THP-1 cells, however it was much less pronounced compared to silica.

Exposure to occupational health hazards among Zambian workers

BACKGROUND

Data on occupational safety and health in Southern Africa are scant. Hence the negative impact of poor working conditions is unknown and the scientific basis for interventions and policy formulation is lacking.

AIMS

To determine the prevalence of, and factors associated with, exposure to occupational health hazards in Zambia.

METHODS

We used data collected in the 2009 National Labour Force Survey. Unadjusted and adjusted odds ratios and their 95% confidence intervals were used to measure magnitudes of associations.

RESULTS

Exposure to occupational hazards among the 64 119 respondents (response rate = 78%) included vibration from hand tools or machinery (3%), temperatures that make one perspire even when not working (4%), low temperatures whether indoors or outdoors (4%), smoke, fume, powder or dust inhalation (13%), pesticides (3%), noise so loud that voice had to be raised to talk to people (4%), chemical handling or skin contact (3%) and exposure to heavy object lifting, frequent bending of the back or rapid movement of limbs causing body pain (30%). In multivariate analysis, exposure to occupational health hazards was associated with older age, male sex, low educational level, being married/cohabiting and not being self-employed.

CONCLUSIONS

Results from this study indicate that Zambian workers are exposed to a broad range of occupational health hazards. This could be useful for the formulation of a multi-sector approach aimed at the prevention and control of hazard exposure.