Arsenic modifies the effect of folic acid in spina bifida prevention, a large hospital-based case-control study in Bangladesh.

BACKGROUND: Spina bifida, a developmental malformation of the spinal cord, is associated with high rates of mortality and disability. Although folic acid-based preventive strategies have been successful in reducing rates of spina bifida, some areas continue to be at higher risk because of chemical exposures. Bangladesh has high arsenic exposures through contaminated drinking water and high rates of spina bifida. This study examines the relationships between mother's arsenic exposure, folic acid, and spina bifida risk in Bangladesh. METHODS: We conducted a hospital-based case-control study at the National Institute of Neurosciences & Hospital (NINS&H) in Dhaka, Bangladesh, between December 2016 and December 2022. Cases were infants under age one year with spina bifida and further classified by a neurosurgeon and imaging. Controls were drawn from children seen at NINS&H and nearby Dhaka Shishu Hospital. Mothers reported folic acid use during pregnancy, and we assessed folate status with serum assays. Arsenic exposure was estimated in drinking water using graphite furnace atomic absorption spectrophotometry (GF-AAS) and in toenails using inductively coupled plasma mass spectrometry (ICP-MS). We used logistic regression to examine the associations between arsenic and spina bifida. We used stratified models to examine the associations between folic acid and spina bifida at different levels of arsenic exposure. RESULTS: We evaluated data from 294 cases of spina bifida and 163 controls. We did not find a main effect of mother's arsenic exposure on spina bifida risk. However, in stratified analyses, folic acid use was associated with lower odds of spina bifida (adjusted odds ratio [OR]: 0.50, 95% confidence interval [CI]: 0.25-1.00, p = 0.05) among women with toenail arsenic concentrations below the median value of 0.46 µg/g, and no association was seen among mothers with toenail arsenic concentrations higher than 0.46 µg/g (adjusted OR: 1.09, 95% CI: 0.52-2.29, p = 0.82). CONCLUSIONS: Mother's arsenic exposure modified the protective association of folic acid with spina bifida. Increased surveillance and additional preventive strategies, such as folic acid fortification and reduction of arsenic, are needed in areas of high arsenic exposure.

Temporal trends of food consumption patterns in Tuvalu under the context of climate change: COMmunity-based Behavior and Attitude survey in Tuvalu (COMBAT) since 2020.

AIM: The aim of this study was to analyze temporal trends of food consumption patterns, attitudes, and health-related knowledge in Tuvalu, a small Pacific Island country facing the triple threat of obesity, climate change, and food insecurity. METHODS: Two waves of the COMmunity-based Behavior and Attitude (COMBAT) survey were conducted in 2020 and 2022. Descriptive characteristics of changes in obesity proportion, food intake, and sociodemographic factors were assessed. Additionally, this study also integrates individual climate data utilizing satellite-based prediction models, and estimates historical temperature, precipitation, and sea level trends among all islands in Tuvalu. RESULTS: The study revealed a high obesity proportion among adults (69.5% in 2020, 73.2% in 2022) and an increase in the percentage of adolescents with a high waist circumference. Variations in food intake were also observed between the two waves of the survey. CONCLUSIONS: The data collected in the COMBAT study provides valuable insights for future epidemiological research to elucidate the associations and causal relationships between climate change, food security, and non-communicable diseases in Tuvalu.

Urine cadmium and urolithiasis: A systematic review and meta-analysis.

Exposure to cadmium may increase risk of urolithiasis, but the results remain inconclusive. This systematic review and meta-analysis aimed to access the association between cadmium exposure and urolithiasis. We searched Medline/PubMed, Embase, Web of Science Core Collection, and Cochrane Central for studies. The primary outcome was the incidence of urolithiasis compared to reference groups. We used relative risk as the summary effect measure. This meta-analysis included eight observational studies and divided into 39 study populations. Among 63,051 subjects, 5018 (7.96%) individuals had urolithiasis. The results indicated that people with an increment of 0.1 µg/g creatinine in urinary cadmium had a 2% increased risk of urolithiasis (pooled relative risk [RR], 1.02; 95% confidence interval [CI], 1.01-1.03) and there is no difference in the risk of urolithiasis in high and low cadmium exposure levels. Meanwhile, people with an increment of 0.1 µg/L in urinary cadmium had a 4% increased risk of urolithiasis (pooled RR, 1.04; 95% CI, 1.02-1.07). Our findings also showed similar associations in both sex, different region (Sweden, China, and Thailand), general and occupational population. The results indicate that cadmium exposure was significantly associated with an elevated risk of urolithiasis. Therefore, it is imperative to take steps to minimize cadmium exposure.

Arsenic modifies the effect of folic acid in spina bifida prevention, a large hospital-based case-control study in Bangladesh.

Background: Spina bifida, a developmental malformation of the spinal cord, is associated with high rates of mortality and disability. Although folic acid-based preventive strategies have been successful in reducing rates of spina bifida, some areas continue to be at higher risk because of chemical exposures. Bangladesh has high arsenic exposures through contaminated drinking water and high rates of spina bifida. Methods: We conducted a hospital-based case-control study at the National Institute of Neurosciences & Hospital (NINS&H) in Dhaka, Bangladesh, between December 2016 and December 2022. Cases were infants under age one year with spina bifida and further classified using data from observations by neurosurgeons and available imaging. Controls were drawn from children who presented to NINS&H or Dhaka Shishu Hospital (DSH) during the same study period. Mothers reported folic acid use during pregnancy, and we assessed folate status with serum assays. Arsenic exposure was estimated in drinking water using graphite furnace atomic absorption spectrophotometry (GF-AAS) and in toenails using inductively coupled plasma mass spectrometry (ICP-MS). Results: We evaluated data from 294 cases of spina bifida and 163 controls. We did not find a main effect of mother's arsenic exposure on spina bifida risk. However, in stratified analyses, folic acid use was associated with lower odds of spina bifida (adjusted odds ratio [OR]: 0.50, 95% confidence interval [CI]: 0.25-1.00, p = 0.05) among women with toenail arsenic concentrations below the median, and no association was seen among mothers with toenail arsenic concentrations higher than median (adjusted OR: 1.09, 95% CI: 0.52-2.29, p = 0.82). Conclusions: Mother's arsenic exposure modified the protective association of folic acid with spina bifida. Increased surveillance and additional preventive strategies, such as folic acid fortification and reduction of arsenic, are needed in areas of high arsenic exposure.

Higher Imported Food Patterns Are Associated with Obesity and Severe Obesity in Tuvalu: A Latent Class Analysis.

Background: Tuvalu is a Pacific Island country within the small island developing states that has observed a significant and alarming increase in obesity rates over the past 40 years, affecting ∼60 %-70 % of the current population. Objectives: This study aimed to investigate the association between food patterns and the proportion of obesity in a Pacific Island country. Methods: The 2022 COMmunity-based Behavior and Attitude survey in Tuvalu (COMBAT) included 985 adults with complete data on sociodemographic information and the frequency of consumption of 25 common foods. A latent class analysis determined 4 food patterns. Bayesian multilevel logistic and linear regression models estimated the association between food patterns and the proportion of obesity [body mass index (BMI) ≥30 kg/m2], severe obesity (BMI ≥40 kg/m2), and weight (kg), adjusting for potential confounders and accounting for clustering by region. Results: The latent class analysis revealed 4 food patterns with an entropy of 0.94 and an average posterior probability of class assignment for each individual of 0.97, described as follows: 1) local: locally produced foods with moderate food diversity (proportion of individuals = 28 %); 2) diverse-local: local with greater food diversity (17 %); 3) restricted-imported: more imported with restricted diversity (29 %); and 4) imported: heavily imported with high diversity (26 %). Compared to those following the diverse-local pattern, the odds of having obesity were greater for those classified with the imported pattern [odds ratio (OR): 2.52; 95 % credible interval (CrI): 1.59, 3.99], restricted-imported pattern (OR: 1.89; 95 % CrI: 1.59, 3.99), and local pattern (OR: 1.54; 95 % CrI: 0.94, 2.50). Similar trends were observed for severe obesity while body weight was positively associated with both restricted-imported and imported food patterns. Conclusions: The high consumption of imported foods, together with the low consumption of plant-based foods and protein-rich foods, could be a relevant modifiable lifestyle factor explaining the high levels of obesity and severe obesity in Tuvalu, a Pacific Island country.

Association between Cesarean section delivery and increased risk of childhood Kawasaki disease.

AIM: Cesarean section delivery is associated with microbiota disruption and immuno-dysregulation during childhood, but the association with Kawasaki disease remains uncertain. We aimed to evaluate the association between Cesarean section and Kawasaki disease. METHODS: We examined the association between Kawasaki disease between six and eighteen months and Cesarean section within a birth cohort of 15,796 mother-infant pairs in Taiwan. The associations were assessed with Poisson regression in the study population, in the 1:2 propensity score-matched subpopulation, and compared with febrile convulsion, trauma and accidents during the same interval as negative control outcomes. RESULTS: Cesarean section was found to increase the risk of Kawasaki disease among overall population (adjusted relative risk [aRR]: 2.22, 95 % confidence interval (CI): 1.14-4.34) and the matched subpopulation (aRR: 2.29, 95 % CI: 1.14-4.68 in PS-matched subpopulation). Meanwhile, there was no association between Cesarean section and the clinic visits for febrile convulsion, trauma and accidents. CONCLUSION: In conclusion, this study identified a potential association between Cesarean section delivery and a higher risk of Kawasaki disease during six-to eighteen months of the prospective birth cohort in Taiwan.

Exploring the link between home garden use and severe obesity: Insights from a nationwide survey in Tuvalu.

Background: Obesity is prevalent and increasing but understudied across Pacific Islanders. Tuvalu is a South Pacific country with a high obesity rate and faces multiple threats of food insecurity. Home garden serves as a sustainable food source and can be a possible intervention for the obesity pandemic in Tuvalu. This study investigated Tuvaluans' home garden use and obesity, and explored factors associated with increased use of home gardens. Methods: We conducted a nationwide, cross-sectional study in Tuvalu during 2022. Structured questionnaires were administered during the in-person interviews, and trained interviewers measured the height and weight of each participant. The association between home garden use, obesity and severe obesity were tested with univariate and multivariable logistic regression. We also applied overlapping weights to balance the distribution of baseline demographic factors. Results: The average body mass index was 34.87 kilogrammes (kg) / square metre (m2) among the study population of 1024 adults (630 from Funafuti and 394 from other islands in Tuvalu). Overall, people having home gardens was associated lower odds for severe obesity compared to those without a home garden in overlap weighting models (odds ratio (OR) = 0.946, 95% CI = 0.897-0.997, P = 0.039) and the association was stronger in Funafuti (OR = 0.927, 95% CI = 0.866-0.991, P = 0.027) than in the outlying islands (OR = 0.967, 95% CI = 0.889-1.052, P = 0.435). Furthermore, increased age was positively associated with having a home garden in Funafuti, and smoking showed an inverse association. Conclusions: Having a home garden is associated with lower odds of severe obesity in Tuvalu, and the association is stronger in Funafuti. Smokers are less likely to have home gardens, and increased age is positively associated with having home gardens. These findings promote more home garden utilisation and provide evidence for targeted interventions in Tuvalu.

Association between maternal shift work during pregnancy child overweight and metabolic outcomes in early childhood.

Background: Previous studies found that maternal shift work during pregnancy was associated with many reproductive hazards, including small for gestational age, preterm birth, stillbirth, and neurodevelopmental impairment. Some studies also showed that these children are more likely to become overweight in early childhood. However, the association with metabolic factors, such as insulin resistance and dyslipidemia, was less studied. Hence, we aimed to understand better the relationship between maternal shift work during pregnancy and the risk of childhood overweight and metabolic outcomes. Confounding factors were also discussed, including diet, exercise, and demographical factors. Methods: We enrolled pregnant women before delivery in the Taiwan Birth Panel Study (TBPS) II conducted between 2010 and 2012, and followed the children of these participants in 2018. The objective of this study is to investigate the influence of prenatal and postnatal factors on infant and early childhood health. During the follow-up in 2018, we checked children's demographic data, obtained blood specimens, and checked their blood sugar, blood insulin, and lipid profiles. Structured questionnaires were used to evaluate demographic data. Multiple linear and logistic regressions were used to examine the associations between maternal shift work during pregnancy and child overweight, metabolic disorders, such as HOMA-IR, and lipid profiles. Results: In this study, we included 407 mother-children pairs with different work shifts (350 day workers and 57 shift workers), and a sub-population without underweight children was also created (290 day workers and 47 shift workers). Shift work during pregnancy was associated with a higher Homeostasis Model Assessment-Insulin Resistance index (HOMA-IR) and a higher odds ratio for overweight in children born from mothers doing shift work during pregnancy after adjustment. The findings were attenuated when we investigated the effect of shift work before pregnancy. Conclusion: Our study suggested that maternal shift work during pregnancy was associated with child overweight and insulin resistance in early childhood.

Risk of SARS-CoV-2 Infection Among Essential Workers in a Community-Based Cohort in the United States.

Objectives: The objective of this paper is to identify the risk factors for SARS-CoV-2 infection that are related to occupation type as well as workplace conditions. Identifying such risk factors could have noteworthy implications in workplace safety enhancement and emergency preparedness planning for essential workers. Methods: We conducted a retrospective analysis of visits at a community-based SARS-CoV-2 testing site in the greater Boston area between March 18th and June 19th, 2020, for individuals between 14 and 65 years of age. Nasopharyngeal swab specimen, medical review, and self-administered questionnaire were obtained, and SARS-CoV-2 infection was determined with real-time, reverse transcriptase-polymerase chain reaction (RT-PCR). Medical record-verified job classification, customer-facing, and work patterns were extracted from each individual's response through chart review and validated by licensed clinicians. The occupational patterns were coded by occupational medicine physicians with pre-specified criteria and were analyzed with logistic regression and inverse probability weighting. Results: Among the 780 individuals included in the final analysis, working in healthcare-related jobs was associated with a four-fold increase in risk of SARS-CoV-2 infection (Adjusted OR: 4.00, 95% CI: 1.45-11.02). Individuals with customer-facing jobs had a two times risk increase (Adjusted OR: 1.97, 95% CI: 1.12-3.45) in having a positive SARS-CoV-2 RT-PCR assay result compared to participants with non-customer facing positions. Conclusions: In this U.S. community-based population during the initial wave of the pandemic, a significant increase in risk of SARS-CoV-2 infection was observed in those employed in the healthcare sector or with customer-facing positions. Further research is warranted to determine if these correlations continued with the buildup of population immunity together with the attenuation of SARS-CoV-2 virulence.

Comparison of COVID-19 mitigation and decompression strategies among homeless shelters: a prospective cohort study.

PURPOSE: To compare the effectiveness of COVID-19 mitigation strategies in two homeless shelters in Massachusetts during the pandemic. METHODS: We conducted a prospective cohort study that followed guests in two Massachusetts homeless shelters between March 30 and May 13, 2020, which adopted different depopulation strategies. One set up temporary tents in its parking lot, while the other decompressed its guests to a gym and a hotel. The outcome was assessed by comparing the odds ratios of positive SARS-CoV-2 RT-PCR assays. RESULTS: Guests residing at the shelter that used temporary tents had 6.21 times (95% CI = 1.86, 20.77) higher odds of testing positive for SARS-CoV-2 at follow-up after adjusting for loss to follow up, age, gender, and race. The daily COVID-19 symptoms checklist performed poorly in detecting positive infection. CONCLUSIONS: The study highlights the importance of depopulating shelter guests with stable and adequate indoor space to prevent SARS-CoV-2 transmission. Daily temperature and symptom checks should be combined with routine testing. With the rising homelessness due to mass unemployment and eviction crisis, our study supports further governmental assistance in decompressing homeless shelters during this pandemic.

Ambient temperature and subsequent COVID-19 mortality in the OECD countries and individual United States.

Epidemiological studies have yielded conflicting results regarding climate and incident SARS-CoV-2 infection, and seasonality of infection rates is debated. Moreover, few studies have focused on COVD-19 deaths. We studied the association of average ambient temperature with subsequent COVID-19 mortality in the OECD countries and the individual United States (US), while accounting for other important meteorological and non-meteorological co-variates. The exposure of interest was average temperature and other weather conditions, measured at 25 days prior and 25 days after the first reported COVID-19 death was collected in the OECD countries and US states. The outcome of interest was cumulative COVID-19 mortality, assessed for each region at 25, 30, 35, and 40 days after the first reported death. Analyses were performed with negative binomial regression and adjusted for other weather conditions, particulate matter, sociodemographic factors, smoking, obesity, ICU beds, and social distancing. A 1 °C increase in ambient temperature was associated with 6% lower COVID-19 mortality at 30 days following the first reported death (multivariate-adjusted mortality rate ratio: 0.94, 95% CI 0.90, 0.99, p = 0.016). The results were robust for COVID-19 mortality at 25, 35 and 40 days after the first death, as well as other sensitivity analyses. The results provide consistent evidence across various models of an inverse association between higher average temperatures and subsequent COVID-19 mortality rates after accounting for other meteorological variables and predictors of SARS-CoV-2 infection or death. This suggests potentially decreased viral transmission in warmer regions and during the summer season.

Associations Between Infant Developmental Delays and Secondhand Smoke Exposure Modified by Maternal Prepregnancy Overweight and Obesity Status.

INTRODUCTION: Secondhand smoke exposure during pregnancy has long been associated with adverse health outcomes in children, but only a few studies have examined its effect modifiers. In this study, we applied effect modification analysis for maternal prepregnancy weight status on detrimental neurodevelopmental effect of secondhand smoke exposure during pregnancy and infancy in a nationwide representative population. AIMS AND METHODS: Term singleton mother-infant pairs with nonsmoking mothers were included for main analysis (N = 15 987) from the Taiwan Birth Cohort Study (TBCS), and were further matched with propensity score (n = 5434). We extracted secondhand smoke exposure during pregnancy and infancy, and eight neurodevelopmental milestones from the responses in the baseline visit at 6 months, and 18-month follow-up of TBCS. The associations between secondhand smoke exposure and neurodevelopmental achievement were analyzed with multivariable logistic regression and Cox model. Propensity score weighting and matching were applied for high-versus-low analysis, and relative excess risk due to interaction were used to estimate effect modification. RESULTS: Higher secondhand smoke exposure was associated with increased likelihood of delayed milestone achievement across gross motor, fine motor, language-related, and social-related domains. The associations in fine motor domains remained observable in propensity score-weighted and -matched models. We identified additive interaction with self-reported maternal overweight and obesity status before pregnancy in milestone development for walking with support, scribbling, and waving goodbye. CONCLUSIONS: Secondhand smoke exposure during pregnancy and infancy were associated with delayed neurodevelopmental milestone achievement at 18 months, and the associations were modified by maternal prepregnancy overweight and obesity status. IMPLICATIONS: The study results suggested the association between maternal secondhand smoke exposure during pregnancy and infancy and delayed fine motor and language-related milestone achievement at 18 months in multivariable, propensity score weighting, and matching populations. The results of positive effect modifications for maternal prepregnancy overweight and obesity status suggested the importance of concurrent interventions on smoke-free environment and maternal health during pregnancy.

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.

Work-related COVID-19 transmission in six Asian countries/areas: A follow-up study.

OBJECTIVE: There is limited evidence of work-related transmission in the emerging coronaviral pandemic. We aimed to identify high-risk occupations for early coronavirus disease 2019 (COVID-19) local transmission. METHODS: In this observational study, we extracted confirmed COVID-19 cases from governmental investigation reports in Hong Kong, Japan, Singapore, Taiwan, Thailand, and Vietnam. We followed each country/area for 40 days after its first locally transmitted case, and excluded all imported cases. We defined a possible work-related case as a worker with evidence of close contact with another confirmed case due to work, or an unknown contact history but likely to be infected in the working environment (e.g. an airport taxi driver). We calculated the case number for each occupation, and illustrated the temporal distribution of all possible work-related cases and healthcare worker (HCW) cases. The temporal distribution was further defined as early outbreak (the earliest 10 days of the following period) and late outbreak (11th to 40th days of the following period). RESULTS: We identified 103 possible work-related cases (14.9%) among a total of 690 local transmissions. The five occupation groups with the most cases were healthcare workers (HCWs) (22%), drivers and transport workers (18%), services and sales workers (18%), cleaning and domestic workers (9%) and public safety workers (7%). Possible work-related transmission played a substantial role in early outbreak (47.7% of early cases). Occupations at risk varied from early outbreak (predominantly services and sales workers, drivers, construction laborers, and religious professionals) to late outbreak (predominantly HCWs, drivers, cleaning and domestic workers, police officers, and religious professionals). CONCLUSIONS: Work-related transmission is considerable in early COVID-19 outbreaks, and the elevated risk of infection was not limited to HCW. Implementing preventive/surveillance strategies for high-risk working populations is warranted.

Association between maternal shift work and infant neurodevelopmental outcomes: results from the Taiwan Birth Cohort Study with propensity-score-matching analysis.

BACKGROUND: Maternal shift work is associated with preterm delivery, small-for-gestational-age new-borns, childhood obesity and future behavioural problems. However, the adverse effects on and interactions of maternal shift work with infant neurodevelopment remain uncertain. Therefore, we examined the associations between maternal-shift-work status and infant neurodevelopmental parameters. METHODS: The Taiwan Birth Cohort Study is a nationwide birth cohort study following representatively sampled mother-infant pairs in 2005. The participants' development and exposure conditions were assessed by home interviews with structured questionnaires at 6 and 18 months of age. Propensity scores were calculated with predefined covariates for 1:1 matching. Multivariate conditional logistic regression and the Cox proportional-hazards model were used to examine the association between maternal-shift-work status and infant neurodevelopmental-milestone-achievement status. RESULTS: In this study, 5637 term singletons were included, with 2098 cases selected in the propensity-score-matched subpopulation. Persistent maternal shift work was associated with increased risks of delays in gross-motor neurodevelopmental milestones [aOR = 1.36, 95% confidence interval (CI) = 1.06-1.76 for walking steadily], fine-motor neurodevelopmental milestones (aOR = 1.39, 95% CI = 1.07-1.80 for scribbling) and social neurodevelopmental milestones (aOR = 1.35, 95% CI = 1.03-1.76 for coming when called upon). Moreover, delayed gross-motor and social development were identified in the propensity-score-matched sub-cohort. CONCLUSIONS: This study shows negative associations between maternal shift work and delayed neurodevelopmental-milestone achievement in the gross-motor, fine-motor and social domains at 18 months. Future research is necessary to elucidate the possible underlying mechanisms and long-term health effects.

Household incense burning and infant gross motor development: Results from the Taiwan Birth Cohort Study.

BACKGROUND: Air pollution from biomass burning were associated with neurodevelopmental deceleration, but limited studies concerned about the effect of indoor biomass burning. Incense burning is a common household ritual practice in Taiwan, while past studies mainly focused on birth weight and allergic disease. OBJECTIVES: We aimed to find the association between incense burning exposure and children's neurodevelopment. METHODS: In Taiwan Birth Cohort Study (TBCS), a nationwide representative birth cohort study, children were assessed upon home interview with structured questionnaires upon six and eighteen months old. Multivariate logistic and Cox proportional hazard regression adjusting confounding factors were applied to explore the odds ratio (OR) and hazard ratio (HR) between household incense burning exposure and caregiver-reported neurodevelopment milestones. RESULTS: In this study, 15,310 term singletons were included, and household incense burning was associated with delay in gross motor neurodevelopment milestone, such as walking with support (Occasional incense burning: OR = 1.26, 95% confidence interval (CI): 1.08 to 1.47, HR = 1.07, 95% CI: 1.03 to 1.11; persistent incense burning: OR = 1.44, 95% CI: 1.22 to 1.69, HR = 1.11, 95% CI: 1.07 to 1.16) and walking steadily (Occasional incense burning: OR = 1.14, 95% CI: 0.98 to 1.32, HR = 1.07, 95% CI: 1.03 to 1.11, persistent incense burning: OR = 1.24, 95% CI: 1.06 to 1.45, HR = 1.09, 95% CI: 1.04 to 1.13). CONCLUSIONS: Our study suggested household incense burning exposure was associated with delay in gross motor neurodevelopmental milestones. Further research is warranted to elucidate the possible mechanism and causal relationship.