A systematic review and meta-analysis of the prevalence and complications of paraphenylenediamine-containing hair dye poisoning in developing countries

BACKGROUND: Suicide is a public health problem, and the number of paraphenylenediamine (PPD)-containing hair dye poisoning with suicidal intentions is increasing in developing countries. In order to better understand this situation, we aimed to conduct a systematic review and meta-analysis to estimate the prevalence and complications associated with hair dye poisoning in developing countries. METHODS: We conducted a systematic review of epidemiological studies using MeSh terms and text keywords to identify studies from the inception to March 2016 about hair dye poisoning with suicidal intentions in developing countries. A meta-analysis was used to calculate the pooled prevalence proportion of hair dye poisoning and its major complications. Data extraction, data analysis, and risk of bias assessment were performed. RESULTS: Thirty-two studies were included in the systematic review and 29 of these studies containing 5,559 subjects covering six countries were included in the meta-analysis. The pooled prevalence proportion of hair dye poisoning with suicidal intentions was 93.5% (95% confidence interval [CI] = 91.6–95.4) with a mortality rate of 14.5% (95% CI = 11.1–17.9). Of these, 73.8% were female, and 26.2% were male (sex ratio: 2.7:1). The occurrence of angioneurotic edema in hair poisoning patients was 67.1% (95% CI = 56.6–77.6), and tracheostomy intervention was considered in 47.9% (95% CI = 22.7–73.2) patients with respiratory distress. Acute renal failure was noticed in 54.7% (95% CI = 34.5–74.9) of the pooled samples and mortality rates were 14.5% (95% CI = 11.1–17.9). The pooled rate of the population studied from Asia and Africa showed 94.6% (95% CI = 92.5–96.7) and 82.9% (95% CI = 70.6–95.3), respectively, ingested hair dye with suicidal intentions. Further, studies carried out in Africa showed slightly higher mortality of 15.1% (95% CI = 6.56–23.7) than the Asians 14.3% (95% CI = 10.5–18.1). CONCLUSION: This meta-analysis provided clear evidence of the prevalence of hair dye poisoning among individuals with suicidal intentions and had given robust evidence for policy making to curtail emerging PPD-containing hair dye poisoning in developing countries.