Secondary analysis finds no clear correlation between indoor pollutants and blood pressure in 4,854 Japanese toddlers

A secondary analysis of 4,854 children in the Japan Environment and Children’s Study found no clear correlations between measured indoor particulate matter, volatile organic compounds and blood pressure at the paired ages examined. According to the abstract, the absolute values of all correlation coefficients were below 0.2. Multiple regression analyses nevertheless identified associations involving specific pollutants, but the authors reported that all such effect sizes were small.

The researchers analyzed data from the Japanese national birth cohort. Indoor concentrations of particulate matter and volatile organic compounds were measured when participants were 1.5 and three years old, while blood pressure was assessed at ages two and four. The analysis used scatter plots to inspect possible relationships and calculated correlation coefficients. Exposure at 1.5 years was compared with blood pressure at age two, and exposure at three years was compared with blood pressure at age four.

The abstract states that m,p-xylene measured at 1.5 years was associated with higher blood pressure at age two. It also reports lower blood pressure in association with PM2.5, p-dichlorobenzene and toluene, without assigning all three pollutants to a specific age-two or age-four outcome in the supplied summary. Benzene measured at age three was associated with lower blood pressure at age four. These regression findings were characterized as small associations and were not presented as evidence that the pollutants caused changes in blood pressure.

Based on the reported results, the authors concluded that exposure to particulate matter and volatile organic compounds at levels sufficient to affect blood pressure in early childhood is unlikely to occur during normal household life. They also cautioned that this conclusion does not eliminate the long-term risks of hypertension or the potential for other diseases. The available report is limited to the study’s abstract and describes an early-access BMC Pediatrics article published on 10 September 2026 that was subject to further edits. Details of measurement procedures, statistical models, participant selection, missing data and the study’s fuller limitations therefore cannot be assessed from the supplied text.

Subject of Research: Associations between indoor air pollutants and blood pressure in toddlers in the Japan Environment and Children’s Study

Article Title: Indoor air pollutants and blood pressure in toddlers: data from the Japan environment and children’s study

Article References: Kanamori, K., Suzuki, T., Ota, C., The Japan Environment, Children’s Study Group, Kamijima, M., Yamazaki, S., Fukami, M., Kishi, R., Koichi, K., Mori, C., Ito, S., Shinohara, R., Inadera, H., Nakayama, T., Kawasaki, R., Takeshima, Y., Kageyama, S., Suganuma, N., Ohga, S., & Katoh, T. (2026). Indoor air pollutants and blood pressure in toddlers: data from the Japan environment and children’s study. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07676-8

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07676-8

Keywords: indoor air pollution, toddler blood pressure, Japan birth cohort, particulate matter, volatile organic compounds, PM2.5, m,p-xylene, benzene, hypertension risk, JECS, Indoor, pollutants