Air pollution and bronchiolitis: a case-control study in Antwerp, Belgium.

This case-control study aimed to investigate the association between short-term (1 to 5 days) and medium-term (31 days) exposure to air pollutants (PM2.5, PM10, BC, NO2) at home/daycare and the risk of 'severe bronchiolitis' (defined as 'requiring hospitalization for bronchiolitis') in children under 2 years in Antwerp, Belgium. We included 118 cases and 79 controls admitted to three general hospitals from October 2020 to June 2021. Exposure levels were predicted using an interpolation model based on fixed measuring stations. We used unconditional logistic regression analysis to assess associations, with adjustment for potential confounders. There were hardly any significant differences in the day-to-day air pollution values between cases and controls. Medium-term (31 days) exposure to PM2.5, PM10, and NO2 was however significantly higher in cases than controls in univariate analysis. Logistic regression revealed an association between severe bronchiolitis and interquartile range (IQR) increases of PM2.5 and PM10 at home and in daycare, as well as IQR increases of NO2 in daycare. Controls were however overrepresented in low pollution periods. Time-adjustment reduced the odds ratios significantly at home for PM2.5 and PM10 (aOR 1.54, 95%CI 0.51-4.65; and 2.69, 95%CI 0.94-7.69 respectively), and in daycare for. PM2.5 (aOR 2.43, 95%CI 0.58-10.1). However, the association between severe bronchiolitis and medium-term air pollution was retained in daycare for IQR increases of PM10 (aOR 5.13, 95%CI 1.24-21.28) and NO2 (aOR 3.88, 95%CI 1.56-9.61) in the time-adjusted model.  Conclusion: This study suggests a possible link between severe bronchiolitis and medium-term (31 days) air pollution exposure (PM10 and NO2), particularly in daycare. Larger studies are warranted to confirm these findings. What is Known: • Bronchiolitis is a leading cause of hospitalization in infants globally and causes a yearly seasonal wave of admissions in paediatric departments worldwide. • Existing studies, mainly from the USA, show heterogeneous outcomes regarding the association between air pollution and bronchiolitis. What is New: • There is a possible link between severe bronchiolitis and medium-term (31 days) air pollution exposure (PM10 and NO2), particularly in daycare. • Larger studies are needed to validate these trends.

Cottage industry as a source of high exposure to lead: A biomonitoring study among people involved in manufacturing cookware from scrap metal.

In low-income countries, a widespread but poorly studied type of cottage industry consists of melting scrap metal for making cookware. We assessed the exposure to lead (Pb) among artisanal workers, and their families, involved in manufacturing cookware from scrap metal. In a cross-sectional survey, we compared artisanal cookware manufacturing foundries with carpentry workshops (negative controls) and car battery repair workshops (positive controls), all located in residential areas, in Lubumbashi (DR Congo). We collected surface dust in the workspaces, and blood and urine samples among workers, as well as residents living in the cookware workshops. Trace elements were quantified in the samples by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In surface dust, median Pb concentrations were higher in cookware foundries (347 mg/kg) than in carpentries (234 mg/kg) but lower than in battery repair workshops (22,000 mg/kg). In workers making the cookware (n = 24), geometric mean (GM) Pb blood cencentration was 118 µg/L [interquartile range (IQR) 78.4-204], i.e. nearly twice as high as among carpenters [60.2 µg/L (44.4-84.7), n = 33], and half the concentration of battery repair workers [255 µg/L (197-362), n = 23]. Resident children from the cookware foundries, had higher urinary Pb [6.2 µg/g creatinine (2.3-19.3), n = 6] than adults [2.3 (2.2-2.5), n = 3]. Our investigation confirms the high Pb hazard linked to car battery repair and reveals a high exposure to Pb among artisanal cookware manufacturers and their families, especially children, in residential areas of a city in a low-income country.

Household air pollution and risk of pulmonary tuberculosis in HIV-Infected adults.

BACKGROUND: In low- and middle-income countries countries, millions of deaths occur annually from household air pollution (HAP), pulmonary tuberculosis (PTB), and HIV-infection. However, it is unknown whether HAP influences PTB risk among people living with HIV-infection. METHODS: We conducted a case-control study among 1,277 HIV-infected adults in Bukavu, eastern Democratic Republic of Congo (February 2018 - March 2019). Cases had current or recent (<5y) PTB (positive sputum smear or Xpert MTB/RIF), controls had no PTB. Daily and lifetime HAP exposure were assessed by questionnaire and, in a random sub-sample (n=270), by 24-hour measurements of personal carbon monoxide (CO) at home. We used multivariable logistic regression to examine the associations between HAP and PTB. RESULTS: We recruited 435 cases and 842 controls (median age 41 years, [IQR] 33-50; 76% female). Cases were more likely to be female than male (63% vs 37%). Participants reporting cooking for >3h/day and ≥2 times/day and ≥5 days/week were more likely to have PTB (aOR 1·36; 95%CI 1·06-1·75) than those spending less time in the kitchen. Time-weighted average 24h personal CO exposure was related dose-dependently with the likelihood of having PTB, with aOR 4·64 (95%CI 1·1-20·7) for the highest quintile [12·3-76·2 ppm] compared to the lowest quintile [0·1-1·9 ppm]. CONCLUSION: Time spent cooking and personal CO exposure were independently associated with increased risk of PTB among people living with HIV. Considering the high burden of TB-HIV coinfection in the region, effective interventions are required to decrease HAP exposure caused by cooking with biomass among people living with HIV, especially women.

Bombé, an undetermined substance that caused an outbreak of illicit drug use in Kinshasa, Democratic Republic of the Congo.

BACKGROUND: Illegal drugs are becoming a public health problem in African cities. In 2021, Bombé, a new drug of unknown composition, caused an outbreak of neuro-psychiatric symptoms in Kinshasa. Bombé was rumored to be based on ground catalytic exhausts stolen from cars. METHODS: The chemical composition of six samples of Bombé obtained from different neighborhoods in Kinshasa was determined by triple quad liquid chromatography-mass spectrometry/mass spectrometry with confirmation by quadrupole time-of-flight mass spectrometry. Metals were determined by inductively coupled plasma-mass spectrometry, and polycyclic aromatic hydrocarbons were measured by gas chromatography-mass spectrometry. RESULTS: Analysis of the Bombé samples revealed that it contained heroin (2-12% of the total area under the curve of the samples) and opioid derivatives, plus paracetamol (33-72%), caffeine (17-26%), and also benzodiazepines (5/6 samples) and cyproheptadine (2/6 samples). The concentrations of neurotoxic metals were unremarkable. The median (range) concentrations of manganese and lead were 9.4 µg/g (range 3-334 µg/g) and 0.36 µg/g (range 0.1-3.12 µg/g ), respectively. All polycyclic aromatic hydrocarbons were below the level of detection (<0.10 µg/g). CONCLUSION: Thanks to international collaboration, Bombé was documented to be a heroin-based drug and its alleged origin from catalytic exhausts was not substantiated. The local human expertise and technical capacity for undertaking toxicological analyses should be increased in Africa.

Erectile dysfunction in copper and cobalt miners: a cross-sectional study in the former Katanga province, Democratic Republic of the Congo.

Background: The African Copperbelt is a site of intense artisanal and industrial mining and refining of copper and cobalt. Aim: We aimed to investigate factors that are possibly associated with erectile dysfunction (ED) in metal miners in the former Katanga province of the Democratic Republic of the Congo. Methods: In a cross-sectional study of 138 miners and 139 controls (bakers), we administered questionnaires to obtain sociodemographic and occupational data and to assess male sexual function (International Index of Erectile Function [IIEF]) and marital relation quality (Revised Dyadic Adjustment Scale). Furthermore, we measured trace metals in blood and urine, as well as testosterone and thyroid hormones in serum. Outcomes: Outcomes included the prevalence of questionnaire-derived ED and the relation of ED with individual characteristics, serum testosterone, and environmental factors. Results: Miners were on average 4 years older than bakers (mean ± SD, 37.5 ± 6.9 vs 33.3 ± 5.7 years). Miners had significantly lower scores than bakers on the IIEF (median [IQR], 66 [49-73] vs 73 [66-74]) and the 3 domains of the Revised Dyadic Adjustment Scale (consensus, satisfaction, cohesion). Free testosterone was significantly lower in miners than bakers (ng/dL; 8.11 [6.90-10.10] vs 10.52 [8.83-12.58]; P ˂ .001). In miners, sex hormone-binding globulin correlated positively with blood Pb and urinary Cd. In a multivariable analysis, mild to moderate ED or moderate ED (IIEF-erectile function score ≤18) was significantly associated with having a mining-related job (adjusted odds ratio [aOR], 2.6; 95% CI, 1.3-5.3), work seniority ˃5 years (aOR, 2.3; 95% CI, 1.1-4.6), alcohol consumption (aOR, 2.8; 95% CI, 1.2-6.7), and aphrodisiacs use (aOR, 4.2; 95% CI, 2.2-8.0). Mediation analysis showed that marital relationship partially mediated the relation between work seniority >5 years in mining and ED. Clinical Implications: The high prevalence of ED found in artisanal mine workers indicates that work-related factors should be considered as possibly contributing, directly or indirectly, to sexual dysfunction in men. Strengths and Limitations: Strengths include being the first epidemiologic study documenting ED with validated questionnaires and its possible determinants, including exposure to toxic metals, among young artisanal miners vs a suitable control group. Limitations are the cross-sectional design with convenience sampling and absence of objective confirmation of ED. Conclusion: As compared with controls, miners reported poorer sexual function and lower quality of their marital relationship, and they had lower free testosterone levels, which may be due to their high exposure to trace metals.

Household Air Pollution and Risk of Pulmonary Tuberculosis in HIV-Infected Adults.

Background: In developing countries, millions of deaths occur annually from household air pollution (HAP), pulmonary tuberculosis (PTB), and HIV-infection. However, it is unknown whether HAP influences PTB risk among people living with HIV-infection. Methods: We conducted a case-control study among 1,277 HIV-infected adults in Bukavu, eastern Democratic Republic of Congo (February 2018 - March 2019). Cases had current or recent (<5y) PTB (positive sputum smear or Xpert MTB/RIF), controls had no PTB. Daily and lifetime HAP exposure were assessed by questionnaire and, in a random sub-sample (n=270), by 24-hour measurements of personal carbon monoxide (CO) at home. We used multivariable logistic regression to examine the associations between HAP and PTB. Results: We recruited 435 cases and 842 controls (median age 41 years, [IQR] 33-50; 76% female). Cases were more likely to be female than male (63% vs 37%). Participants reporting cooking for >3h/day and ≥2 times/day and ≥5 days/weekwere more likely to have PTB (aOR 1·36; 95%CI 1·06-1·75) than those spending less time in the kitchen. Time-weighted average 24h personal CO exposure was related dose-dependently with the likelihood of having PTB, with aOR 4·64 (95%CI 1·1-20·7) for the highest quintile [12·3-76·2 ppm] compared to the lowest quintile [0·1-1·9 ppm]. Conclusion: Time spent cooking and personal CO exposure were independently associated with increased risk of PTB among people living with HIV. Considering the high burden of TB-HIV coinfection in the region, effective interventions are required to decrease HAP exposure caused by cooking with biomass among people living with HIV, especially women.

Transplacental transfer of cobalt: Evidence from a study of mothers and their neonates in the African Copperbelt.

BACKGROUND: Transfer of the trace metal cobalt (Co) from mother to foetus has not been documented in populations with high environmental exposure to Co, as is the case in the African Copperbelt mining region. We analysed data obtained from 246 mother-infant pairs included (at delivery) in a previously published case-control study on birth defects, done in Lubumbashi (Democratic Republic of Congo) between March 1, 2013, and Feb 28, 2015. METHODS: Co was measured by Inductively Coupled Plasma Mass Spectrometry in maternal blood, maternal urine, umbilical cord blood and placental tissue, as available. RESULTS: The Co concentrations [geometric mean (GM) with interquartile range (IQR)] in maternal blood (GM 1.77 µg/L, IQR 1.07-2.93) and urine (GM 7.42 µg/g creatinine, IQR 4.41-11.0) were highly correlated (Spearman r = 0.71, n = 166; p < 0.001) and considerably higher than reference values determined for general populations elsewhere in the world. The concentrations of Co in umbilical cord blood (GM 2.41 µg/L) were higher (Wilcoxon test, p < 0.001) than in maternal blood (GM 1.37 µg/L), with a correlation between both values (Spearman r = 0.34; n = 127, p < 0.001). Co concentrations in placental tissue (geometric mean 0.02 µg/g wet weight) correlated with concentrations in maternal blood (Spearman r = 0.50, n = 86, p < 0.001) and in neonatal blood (Spearman r = 0.23, n = 83, p = 0.039). CONCLUSION: This first study of maternal and neonatal Co concentrations in the African Copperbelt provides strong evidence of a high transfer of Co from mother to foetus.

What criteria are used in the investigation of alleged cases of research misconduct?

Research misconduct is a global concern. Considerable research has been devoted to guidance documents, but little attention has been paid to the empirical investigation of how (alleged) cases of research misconduct are addressed in real-life and which criteria are used to qualify a case as misconduct. Therefore, we performed a content analysis of 169 closed misconduct reports between 2007 and 2017 from Denmark, the Netherlands and Belgium, representing three different types of governance of research misconduct. This study showed that when considering a case of (alleged) misconduct investigating committees assess 1) the objective evidence of research misconduct, 2) the subjective intent of the person subject to investigations, and 3) case specific circumstances. We found that research misconduct was established in 15% (9/61) of cases in Denmark; 16% (13/82) in the Netherlands and 38% (10/26) in Belgium. 57% (35/61) of cases in Denmark, 49% (40/82) in the Netherlands, and 12% (3/26) in Belgium were deemed outside of the scope of the investigating committee. Our analysis improves the understanding of how investigations of (alleged) misconduct are handled by the investigating committees in Europe.

Reducing disease and death from Artisanal and Small-Scale Mining (ASM) - the urgent need for responsible mining in the context of growing global demand for minerals and metals for climate change mitigation.

Artisanal and small-scale mining (ASM) takes place under extreme conditions with a lack of occupational health and safety. As the demand for metals is increasing due in part to their extensive use in 'green technologies' for climate change mitigation, the negative environmental and occupational consequences of mining practices are disproportionately felt in low- and middle-income countries. The Collegium Ramazzini statement on ASM presents updated information on its neglected health hazards that include multiple toxic hazards, most notably mercury, lead, cyanide, arsenic, cadmium, and cobalt, as well as physical hazards, most notably airborne dust and noise, and the high risk of infectious diseases. These hazards affect both miners and mining communities as working and living spaces are rarely separated. The impact on children and women is often severe, including hazardous exposures during the child-bearing age and pregnancies, and the risk of child labor. We suggest strategies for the mitigation of these hazards and classify those according to primordial, primary, secondary, and tertiary prevention. Further, we identify knowledge gaps and issue recommendations for international, national, and local governments, metal purchasers, and employers are given. With this statement, the Collegium Ramazzini calls for the extension of efforts to minimize all hazards that confront ASM miners and their families.

Do biomedical researchers differ in their perceptions of plagiarism across Europe? Findings from an online survey among leading universities.

BACKGROUND: Existing research on perceptions of plagiarism and cultural influences mainly focuses on comparisons between the Western World and the Eastern World. However, possible differences within the Western World have hardly been assessed, especially among biomedical academics. The authors compared perceptions of plagiarism among European biomedical researchers who participated in an online survey. METHODS: The present work is based on the data collected in a previous online survey done in 2018 among biomedical researchers working in leading European and Chinese universities. Respondents based in Europe were grouped into three geographical regions (northern Europe, southern Europe and northwestern Europe) and their responses were analyzed using logistic regression analysis with adjustments for demographic factors. RESULTS: Data were available from 810 respondents (265 northern Europe, 101 southern Europe, 444 northwestern Europe). In addition to their generally similar responses, different perceptions of plagiarism were observed among respondents in the three European regions. In summary, among the three European regions, Nordic respondents identified the most types of practices as plagiarism. Compared to the southern respondents, Nordic and northwestern respondents were more likely to consider less evident practices as plagiarism, such as Rephrasing another person's work without crediting the source [aORN|S 1.99 (95%CI 1.08;3.67), aORS|NW 0.50 (95%CI 0.28;0.91)] and With permission from the original author, using another's text without crediting the source [aORN|S 3.16 (95%CI 1.90;5.25), aORS|NW 0.26 (95%CI 0.16;0.42)]. In contrast, the southern respondents were the most inclined to recognize recycling of one's previously rejected research proposal as plagiarism. CONCLUSIONS: In spite of a generally similar response pattern, the present study indicates different perceptions of plagiarism among European biomedical researchers. These intra-European differences should be considered when addressing plagiarism.

Occupational Asthma Caused by Low-Molecular-Weight Chemicals Associated With Contact Dermatitis: A Retrospective Study.

BACKGROUND: Occupational asthma (OA) may have different etiologies, but it is not clear whether the etiologic agents influence the clinical presentation, especially the co-occurrence of skin lesions. OBJECTIVE: To determine the impact of different asthmagens on the characteristics of OA, with a focus on the occurrence of prior or concomitant skin disorders. METHODS: In a retrospective analysis of patients who visited the Occupational and Environmental Disease Clinic of a tertiary referral hospital from 2009 to 2019, we classified patients into definite, probable, or possible OA according to prespecified diagnostic guidelines. In multivariate logistic regression with sensitivity analysis, we examined the relation of high- and low-molecular-weight (HMW and LMW) agents with the clinical presentation. RESULTS: Of 209 cases of OA, 66 were caused by HMW agents and 143 by LMW agents. Patients with OA exposed to LMW agents had higher odds of having (had) allergic contact dermatitis (odds ratio, 5.45 [1.80-23.70]; P < .01), compared with patients exposed to HMW agents. Conversely, HMW agents were associated with higher odds of rhinitis symptoms (odds ratio of LMW/HMW, 0.33 [0.17-0.63]; P < .001) and high total IgE (odds ratio of LMW/HMW, 0.35 [0.17-0.70]; P < .01). Risk factors for having coexisting contact dermatitis included construction work, hairdressing, and exposure to metals or epoxy resins. CONCLUSIONS: Among patients with OA, exposure to specific LMW agents was associated with a high frequency of contact dermatitis. Different types of asthmagens within HMW or LMW agents appear to determine the phenotype and comorbidity of OA.

Residential green space and mental health-related prescription medication sales: An ecological study in Belgium.

BACKGROUND: Residential green space has been associated with mental health benefits, but how such associations vary with green space types is insufficiently known. OBJECTIVE: We aimed to investigate associations between types and quantities of green space and sales of mood disorder medication in Belgium. METHODS: We used aggregated sales data of psycholeptics and psychoanaleptics prescribed to adults from 2006 to 2014. Generalized mixed effects models were used to investigate associations between relative covers of woodland, low-green, grassland, and garden, and average annual medication sales. Models were adjusted for socio-economic background variables, urban-rural differences, and administrative region, and included random effects of latitude and longitude. RESULTS: Urban census tracts were associated with 9-10% higher medication sales. In nationwide models, a 10% increase in relative cover of woodland, garden, and grass was associated with a 1-2% decrease in medication sales. The same association was found for low green but only for men. In stratified models, a 10% increase in relative cover of any green space type in urban census tracts was associated with a decrease of medication sales by 1-3%. In rural census tracts, no protective associations between green space and mood disorder medication sales were observed, with the exception of relative woodland cover for women (-1%), and low green was associated with higher medication sales (+6-7%). CONCLUSIONS: Taken together, these results suggest that living in green environments may be beneficial for adult mental health. Woodland exposure seemed the most beneficial, but the amount of green space was more important than the type. Results underline the importance of conserving green space in our living environment, for the conservation of biodiversity and for human health.

Identifying cleaning products associated with short-term work-related respiratory symptoms: A workforce-based study in domestic cleaners.

Domestic cleaners have an increased risk of asthma-like and other respiratory symptoms and conditions. Uncertainty exists about which products are most hazardous. We aimed to investigate, among professional domestic cleaners, the associations of ocular/respiratory outcomes with using specific types of products at work and with the ability to choose their own products. Among domestic cleaners employed by "service vouchers" companies in Belgium, we administered an online questionnaire on ocular/respiratory symptoms (frequency and time relation to workdays), frequency of use of 40 types of products, and ability to choose one's own products. Work-relatedness was defined as symptoms improving/disappearing on days off-work. We studied associations between frequency of product-use with work-related outcomes (eye irritation, rhinitis symptoms, sore throat, laryngeal symptoms, asthma symptoms, cough) and with chronic bronchitis, using multivariable logistic and elastic net regression. Adjusted odds ratios (OR) with 95%-confidence intervals were obtained per time a product was used per week. Among 1,586 domestic cleaners (99% women), the number of times sprays were used (median 13/week) was significantly associated with all outcomes (ORs between 1.012 and 1.024 per time sprays were used per week). Bleach/disinfectant-containing liquid products were associated with all outcomes, except for laryngeal symptoms (ORs 1.086 to 1.150); ammonia with work-related upper airway symptoms and chronic bronchitis. Cleaners able to choose their own products had fewer work-related eye symptoms (OR 0.728;0.556-0.954), rhinitis (OR 0.735;0.571-0.946) and cough (OR 0.671;0.520-0.865). Using elastic net regression, work-related rhinitis was most strongly associated with mould removal spray (OR 1.108;1.006-1.248), carpet/seat/curtain spray (OR 1.099;1.001-1.304) and ammonia (OR 1.081;1.002-1.372); work-related asthma with carpet/seat/curtain spray (OR 1.103;1.017-1.322), mould removal spray (OR 1.029;0.995-1.199) and drain cleaner (OR 1.023;0.979-1.302). In a large group of domestic cleaners, we documented that cleaning products have a range of adverse respiratory effects. Empowering cleaners to choose their products may reduce the burden of symptoms.

Disease mapping method comparing the spatial distribution of a disease with a control disease.

Small-area methods are being used in spatial epidemiology to understand the effect of location on health and detect areas where the risk of a disease is significantly elevated. Disease mapping models relate the observed number of cases to an expected number of cases per area. Expected numbers are often calculated by internal standardization, which requires both accurate population numbers and disease rates per gender and/or age group. However, confidentiality issues or the absence of high-quality information about the characteristics of a population-at-risk can hamper those calculations. Based on methods in point process analysis for situations without accurate population data, we propose the use of a case-control approach in the context of lattice data, in which an unrelated, spatially unstructured disease is used as a control disease. We correct for the uncertainty in the estimation of the expected values, which arises by using the control-disease's observed number of cases as a representation of a fraction of the total population. We apply our methods to a Belgian study of mesothelioma risk, where pancreatic cancer serves as the control disease. The analysis results are in close agreement with those coming from traditional disease mapping models based on internally standardized expected counts. The simulation study results confirm our findings for different spatial structures. We show that the proposed method can adequately address the problem of inaccurate or unavailable population data in disease mapping analysis.

Occupational rhinitis and asthma in bakers: a cross-sectional study in the former Katanga province of DR Congo.

OBJECTIVE: Bakers are at high risk of rhinitis and asthma, but the prevalence of these occupational diseases is not well known in Sub-Saharan Africa. We investigated the prevalence of occupational rhinitis and asthma among industrial bakers in the former province of Katanga. METHODS: In a cross-sectional study conducted in eight towns from October 2018 to September 2019, we included 276 male workers from 18 industrial bakeries and 113 male controls (35 butchers and 78 bread sellers), all nonsmokers. Participants replied to a validated questionnaire (European Community of Respiratory Health Survey II), administered face to face, and performed spirometry at the work place. In 15 bakers with symptoms of work-related asthma, records of self-measured peak expiratory flow (PEF) 4 times per day during 4 weeks were analyzed by the OASYS (Occupational Asthma System) protocol. RESULTS: The bakers and controls did not differ by age (32.2 ± 7.3 y vs 32.8 ± 10.3 y). According to the questionnaire, work-related rhinitis and asthma were significantly more prevalent among bakers (31% and 5%, respectively) than among controls (2% and 0%, respectively). However, the groups did not differ significantly with regard to spirometric parameters. Based on PEF records, 10 out of 15 were positive for occupational asthma (OASYS score > 2.5), so the rate of occupational asthma was 3.6% in this study. CONCLUSION: This first study in DR Congo demonstrates the existence of occupational rhinitis and asthma among industrial bakers in Katanga. Further epidemiological studies are needed to clarify the extent and risk factors of baker's asthma in the area. In the meantime, advocacy and implementation of appropriate occupational hygiene measures are warranted to protect bakery workers in DR Congo.

High temperatures trigger suicide mortality in Brussels, Belgium: A case-crossover study (2002-2011).

BACKGROUND: Temperature may trigger the risk of suicide, however, the extent and shape of the associations show geographical variation. Here, we investigate the short-term effects of temperature on suicide deaths occurring in Brussels between January 1st, 2002 and December 31st, 2011. METHODS: We conducted a bidirectional time-stratified case-crossover study with cases being suicide deaths occurring among Brussels residents aged 5 years or older. Cases were matched by day of the week with control days from the same month and year. The exposure was the daily average temperature measured at the Uccle station (Brussels) and obtained from the Belgian Royal Meteorological Institute. We combined conditional logistic regression with distributed lag non-linear models (DLNM) to obtain one week (lag 0-6) cumulative risk ratios (RR) and their 95% confidence intervals (CI) for the effects of moderate and extreme cold (5th and 1st percentiles of temperature, respectively) and moderate and extreme heat (95th and 99th percentiles of temperature, respectively), relative to the median temperature. RESULTS: In total, 1891 suicide deaths were included. The median temperature was 11.6 °C, moderate and extreme cold temperatures were 0 and -3.1 °C, respectively, and moderate and extreme high temperatures were 20.9 and 24.4 °C, respectively. The cumulative risk of suicide mortality was almost twice higher among lags 0 to 6 for both moderate and extreme heat, relative to the period median temperature (e.g. moderate heat RR = 1.80 CI:1.27-2.54). No statistically significant associations were observed for cold temperatures. CONCLUSIONS: In Brussels, a western European city with temperate climate, high temperatures may trigger suicide deaths up to one week later. In the context of climate change, adaptation strategies must take into consideration the effects of temperature on mental health.