Decrease in nickel sensitization in a Danish schoolgirl population with ears pierced after implementation of a...

Area of Science:

• Dermatology
• Environmental Health
• Epidemiology

Background:

• Danish Ministry of Environment implemented a nickel-exposure regulation in 1992.
• European Union countries have adopted similar expanded regulations.
• The regulation aimed to reduce skin nickel exposure in the population.

Purpose of the Study:

• Evaluate the impact of the 1992 Danish nickel regulation on nickel sensitization prevalence.
• Investigate nickel sensitization in girls based on ear-piercing timing relative to the regulation.
• Assess the relationship between ear piercing, age, and nickel allergy.

Main Methods:

• Combined patch testing and questionnaire study of girls in public schools (pierced post-1992) and high schools (pierced pre-1992).
• Recruited 427 public school girls (mean age 12.4) and 534 high school girls (mean age 18.8).
• Utilized multivariate logistic regression to analyze factors influencing nickel sensitization prevalence.

Main Results:

• Nickel sensitization prevalence was significantly higher in girls pierced before 1992 (17.1%) compared to those pierced after (3.9%).
• Ear piercing before 1992 increased nickel sensitization prevalence (odds ratio 3.34), while piercing after 1992 showed a minimal effect (odds ratio 1.20).
• A potential protective effect of wearing oral braces before ear piercing was observed but not statistically significant.

Conclusions:

• The 1992 Danish nickel regulation has demonstrably protected the female population from developing nickel allergy.
• Ear piercing timing relative to the regulation is a critical factor in nickel sensitization.
• The study strongly suggests the regulation's success in preventing nickel allergy.