Satish Kumar DDS, MDSc
Health care workers (HCWs) are at increased risk of sensitization and allergic symptoms (S&AS) to natural rubber latex (NRL) as compared to the general adult population.
The increase in risk of sensitization and allergic symptoms to NRL in HCW’s is difficult to quantify due to limited data from the general population and non-standardized allergy tests that produced inconsistent results.
Do the incidence and prevalence and incidence rates of natural rubber latex (NRL) sensitization or allergy in Health care workers (HCWs) differ from than those observed in non-HCWs? Is there a dose-response relationship among HCWs, NRL glove exposure and sensitization and allergic symptoms (S&AS)? Does changing gloves mitigate S&AS?
The authors searched 2 databases to December 31, 2003. The authors used specific exclusion and inclusion criteria to screen for articles. The data were extracted in a standardized manner and examined by 2 experts and reviewed by the group chairperson. The authors performed a meta-analysis of qualified studies to estimate the risk of sensitization, clinical allergy and the effect of NRL exposure on the different allergic symptoms in HCWs and the general population. Combined prevalence rates of NRL allergy were obtained from the separate prevalence rates of the qualified studies according to whether HCWs were hospital workers with or without a job specification; whether the general adult population was non-selected or had a history of allergy, asthma or both conditions; and according to the presence or absence of information on the participation rate in the studies that was calculated by using the number of participants who underwent immunologic testing (either skin prick testing or specific IgE antibody assessment) as the numerator and the target population as the denominator. The studies reporting on the incidence of NRL allergy and effect of interventions such as use of non-powdered gloves on NRL allergy in HCWs were described but not combined due to insufficient data.
IgE-mediated allergy to NRL ranges from 4.03% (n=5784; 95% CI 3.53-4.53) in the HCWs with unknown participation rates to 4.79% (n=8086; 95% CI 4.12-5.46) in the HCWs with known participation rates. IgE-mediated allergy to NRL ranges from 1.37% (n=583; 95% CI 0.43-2.31) in the non-selected general population to 1.65% (n=424; 95% CI 0.45-2.28) in the general population who are allergic subjects, asthmatic subjects or both. NRL-positive skin prick test responses in all HCWs with known participation rate was higher [7.83% (n=9056; 95% CI 6.84-7.90)] than in the non-selected, asymptomatic general population [2.08% (n=1301; 95% CI 1.31-2.85)], however, this was lower for NRL-specific IgE in HCWs with known participation rate [7.40% (n=5368; 95% CI 6.71-8.09)] than in the non-selected, asymptomatic general population [10.27% (n=16,803; 95% CI 9.82-10.72)]. HCWs exposed to latex gloves showed an increased risk of hand dermatitis [n=8358; odds ratio (OR), 2.46; 95% CI, 2.11-2.86], asthma or wheezing [n=6710; OR 1.55; 95% CI 1.15-2.08], rhinoconjunctivitis [n=4602; OR 2.73; 95% CI 1.97-3.81], and at least one generic symptom [n=8261; OR 1.27; 95% CI 1.09-1.47]. Sensitization to latex was significantly associated with asthma [OR 3.95; 95% CI 2.74-5.70], and rhinoconjunctivitis [OR 5.70; 95% CI 3.13-10.39]. The incidence rate of sensitization and allergy to NRL and the effect of interventions such as glove-changing policies are inconclusive because of the design of the studies.
Health care workers have an increased risk of sensitization and allergic symptoms to latex.
Source of Funding:
Importance and Context:
NRL is a recognized allergen and a known cause of allergy among HCWs and the general population. NRL is believed to be one of leading causes of occupational asthma in HCWs. One prior systematic review (1) concluded that HCWs exposed to NRL were not at higher risk of an IgE-mediated sensitization than the general population.
Strengths and Weaknesses of the Systematic Review:
In this systematic review, the authors used acceptable methods to identify, select and analyze qualified studies. However, the following are study weaknesses: the authors did not provide quality ratings of the studies; they combined the results from studies that used different allergy testing methods (skin prick tests performed with commercial and home-made extracts and different serum latex-specific IgE tests); and they did not attempt any sensitivity testing by combining subsets of studies that used the same latex-specific IgE test. The authors also reported incorrect prevalence figures in Table I that were eventually identified in an erratum (2). The authors did not attempt to explain the surprising finding that the general population had a much higher rate of NRL-specific IgE compared to HCWs. Further, they did not state whether or not they searched non-English language and grey literature sources. One of the authors (Flahault, A) reported a potential conflict of interest.
Strengths and Weaknesses of the Evidence:
There are an adequate number of good quality studies of NRL allergy among HCWs, but there is a paucity of studies examining the same in non-selected, asymptomatic general populations (only 3 studies qualified for this review). The inconsistent use of allergy testing methods across studies could have affected the meta-analysis results. The incidence of sensitization and allergy to NRL and the effect of intervention such as glove changing policies on NRL allergy were inconclusive because of few available studies.
Implications for Dental Practice:
Because oral health care providers are at increased risk of sensitization and allergic symptoms to latex, prevention of exposure to latex allergen is prudent. Although they are considered to present weak evidence, a few studies show that the use of non-powdered latex gloves or use of non-latex gloves by sensitized subjects may be effective in reducing the risk of allergic symptoms to latex. REFERENCES: (1) Garabrant DH, Schweitzer S. Epidemiology of latex sensitization and allergies in health care workers. J Allergy Clin Immunol 2002;110(suppl): S82-95. (2) Comment in: J Allergy Clin Immunol. 2007 Jun; 119(6):1561; author reply 1561.