Fig. 3: PFOA concentration distribution across Sweden.

A Illustration of the six larger regions in Sweden, based on how healthcare is organized in Sweden. B Illustrates the six larger regions’ mean concentration (ng/mL) of PFOA. C Concentration distribution (log₂ ng/mL) of PFOA and the P values for region comparisons. Analysis was made on individuals with MS (n = 907) and matched controls (n = 907), adjusting for age, sex, sample collection year, BMI at the sample time point, BMI at the age of 20, treatment, years of regular smoking, years of irregular smoking, years of passive smoking (indoor environment), number of childbirths, and disease phenotype. Comparisons were made between all six regions using estimated marginal means based on a linear mixed-effect regression model and P values for the two-sided tests were computed using Satterthwaite’s degrees of freedom method. Only significant P values were included in the boxplot. No adjustments were made for multiple comparisons. Moreover, the upper and lower whiskers indicate 1.5 times the interquartile range from above the upper quartile and below the lower quartile. Source data are provided as a Source Data file.