Contribution of authorship
All authors approved the final manuscript. H.K. initiated the concept and H. N. designed the study. T.M. and T.F. provided additional advice. A.S., Y.O., and M.K. collected the data. H.K. analysed the data and wrote the manuscript. A.K., S.Y, M.H., K.F., S.Y., K.H., and the Japan Environment and Children’s Study group reviewed the manuscript and gave critical advice.