The association between hand eczema and nickel allergy has weakened among young women in the general population following the Danish nickel regulation: results from two cross‐sectional studies

BACKGROUND: An association between nickel contact allergy and hand eczema has previously been demonstrated. In 1990, Denmark regulated the extent of nickel release in the ear-piercing process as well as nickel release from consumer products. OBJECTIVES: This study aimed to evaluate the effect of the Danish nickel regulation by comparing the prevalence of concomitant nickel allergy and hand eczema observed in two repeated cross-sectional studies performed in the same general population in Copenhagen. MATERIALS: In 1990 and 2006, 3881 18-69 year olds completed a postal questionnaire and were patch tested with nickel. Data were analysed by logistic regression analyses and associations were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: The prevalence of concomitant nickel contact allergy and a history of hand eczema decreased among 18-35-year-old women from 9.0% in 1990 to 2.1% in 2006 (P < 0.01). The association between nickel contact allergy and a history of hand eczema decreased in this age group between 1990 (OR = 3.63; CI = 1.33-9.96) and 2006 (OR = 0.65; CI = 0.29-1.46). Among older women, no significant changes were observed in the association between nickel contact allergy and hand eczema. CONCLUSIONS: Regulatory control of nickel exposure may have reduced the effect of nickel on hand eczema in the young female population.