High Incidence of Atopic Dermatitis among Children Whose Fathers Work in Primary Industry: The Japan Environment and Children's Study (JECS).

Hiroshi Yokomichi,Yuka Akiyama,Zentaro Yamagata,Megumi Kushima,Reiji Kojima,Kunio Miyake,Tadao Ooka,Sayaka Horiuchi,Ryoji Shinohara,Mie Mochizuki,Sanae Otawa

doi:10.3390/ijerph19031761

Hiroshi Yokomichi, Yuka Akiyama + Show 9 more

Open Access

https://doi.org/10.3390/ijerph19031761

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Abstract

The hygiene hypothesis assumes a low incidence of allergic diseases in families engaging in farming work. However, a few studies have indicated rural life as a potential risk factor for atopic dermatitis (AD). Using a large Japanese birth cohort dataset, we calculated the accumulated incidence of AD in children aged 6 months and 1, 2, and 3 years by family business and the hazard ratio. We adjusted for confounding factors. The father’s job was considered the family business. We analysed data on 41,469 father–child pairs at 6 months of age, 40,067 pairs at 1 year, 38,286 pairs at 2 years, and 36,570 pairs at 3 years. We found the highest accumulated incidence of AD among children with fathers engaged in primary industry, with 2.5% at the age of 6 months, 6.6% at 1 year, 12.0% at 2 years, and 15.4% at 3 years. Among primary industry occupations, forestry was associated with the highest incidence of AD across these ages. The hazard ratio of AD was also highest for children whose family business was primary industry. In conclusion, the highest incidence and hazard ratio of AD were observed among children whose fathers worked in primary industry.

Highlights

Atopic dermatitis (AD) is more prevalent in industrialised countries than in developing nations [1]
Children whose fathers worked in agriculture, forestry, or fisheries had the highest incidence of AD
Among these three primary industries, agriculture showed a high incidence of AD (2.4% at 6 months of age, 5.9% at 1 year, 10.8% at 2 years, and 13.3% at 3 years), and forestry showed the highest incidence in the same age groups

Summary

Introduction

Atopic dermatitis (AD) is more prevalent in industrialised countries than in developing nations [1]. A study from Sweden showed that children who grew up with farm animals and those who ate fish had a lower incidence of allergic rhinitis [4]. This evidence suggests that, in industrialised nations, children in farming households should have a relatively low prevalence of AD. In a British birth cohort study, a farm residence was associated with a 10% decrease in the incidence of AD in children, this relationship was nonsignificant [6]. A Finnish population study reported a nonsignificant association between a farm residence and a lower incidence of AD [7]. There may be a developing consensus that a rural residence is a preventive environmental factor for AD [8]

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Conclusion