This cross-sectional analytical study aimed to explore the relationship between latex sensitization and extractable protein levels. The choice of this research design was deemed suitable due to the continuous and natural occurrence of exposure. However, the number of participants undergoing specific IgE measurements was limited, potentially resulting in inadequate statistical power. To address this, the authors attempted to recalculate the sample size, revealing a lower requirement. Notably, a study in Italy reported a significant decrease in positive latex skin prick test cases among healthcare workers following the banning of powdered latex gloves, with prevalence dropping from 5.9 to 0% over eight years [17]. Recalculating our sample size in accordance with these results yielded estimates of 106 participants in the low protein group and 212 in the high protein group, aligning more closely with the actual participant numbers in our study. Moreover, from a biomedical perspective, the lower levels of extractable protein observed in our study compared to previous studies [9, 18, 19] may lead to fewer cases of latex sensitization. Thus, increasing the sample size might not notably change the observed prevalence of latex sensitization in both exposure groups and would likely not distort the overall findings. Additionally, when discussing the research tools in this study, it’s essential to weigh the pros and cons of latex skin prick tests and latex-specific IgE measurement. While latex skin prick tests may offer higher sensitivity and specificity compared to the latter, the lack of standardized reagents in the market poses challenges. This limitation can potentially reduce sensitivity on detecting latex sensitization and increase the risk of adverse reactions [20]. On the other hand, specific IgE measurement, with a demonstrated sensitivity of 76.3% and specificity of 96.7%, provides a reliable and reproducible method for determining latex sensitization [16].

Our study found that while demographic data did not significantly differ between the low and high protein groups, several exposure factors, including job characteristics and glove usage patterns (such as duration of glove exposure per day and frequency of glove use), exhibited notable disparities. This was attributed to the different working characteristics of the participants in the operating theatre and inpatient department. The non-powdered latex gloves exposure group consists of nursing staff primarily stationed in operating theaters, where the nature of their work requires them to wear gloves for extended durations during surgical procedures. In contrast, the powdered latex gloves exposure group comprises nursing staff stationed in inpatient care or intensive care units, where the use of gloves is more frequent but of shorter duration, as they change gloves regularly while attending to patients on a case-by-case basis.

Latex allergy is an IgE-mediated hypersensitivity reaction that arises from exposure to latex allergens. The higher the levels of latex allergen exposure, the higher the chance of developing latex sensitization. However, our study cannot demonstrate the significant differences in latex sensitization between low and high protein groups (4.1% vs. 2.2%). This discrepancy can be attributed to the comparable extractable protein levels in both high (powdered) and low protein (non-powdered) gloves. The lower levels of extractable protein (53.0-56.9 µg/g) observed in powdered latex gloves (classified as high protein gloves in our study) compared to levels reported in previous studies (generally higher than 100 µg/g) [9, 19] may account for the lack of significant differences in latex sensitization cases. In recent years, advancements in latex glove production, such as in-line high-temperature processes and post-washing procedures, have led to a significant decrease in extractable protein levels [9]. A striking contrast can be observed when comparing studies published in 2003 and 2016; the extractable protein levels in latex gloves from Germany in 2003 were as high as 917.38 µg/g, and 68.4% of these gloves exceeded the DGUV recommended limit of 30 µg/g (TRGS 540) [19]. In contrast, a study published in 2016 reported that the extractable protein content in latex gloves in Germany had significantly decreased to 92.3 µg/g, with only 27.8% of all gloves in that study exceeding the DGUV recommended limit [21]. Moreover, our study found lower extractable protein levels in currently used latex gloves (lower limit of detection – 33.6 µg/dm2) when compared to the gloves examined in earlier studies in our country (115.1–203.9 µg/dm2) [18]. These earlier studies demonstrated a higher prevalence of latex sensitization among health workers (4.7%) compared to our research (2.8%) [18]. This serves as evidence of the technological improvements in glove production, which have likely contributed to the reduction in latex allergen levels and, consequently, the absence of significant differences in latex sensitization observed in our study.

In contrast, our study highlights that nursing staff in the low protein group, who were exposed to non-powdered latex gloves with lower extractable protein, had significantly fewer latex allergy symptoms than those in the high protein group (1.2% vs. 7.2%, OR 0.16, 95%CI: 0.03, 0.59), who were still exposed to powdered latex gloves with higher extractable protein. This difference persisted even after adjusting for various factors, as shown in Table 4 (adjusted OR 0.18, 95% CI: 0.04, 0.86). This phenomenon may be explained by the fact that the use of powdered latex gloves increases the risk of developing latex allergy symptoms [6, 22, 23]. Not only extractable protein in latex gloves but also powdered in latex gloves can increase the risk of latex allergy symptoms. There are various explanations for this. The presence of glove powder can significantly impact skin integrity by inducing roughness and compromising the natural skin barrier, thereby elevating the risk of exposure to latex allergens, and subsequently increasing the likelihood of adverse allergic reactions [24]. This elucidates why individuals in the low protein group, where powder usage was eliminated, reported lower occurrences of current latex allergy symptoms compared to both the high protein group and previous studies. Additionally, powdered latex gloves can produce latex-aeroallergen in the workplace, causing a higher chance of latex-allergen exposure, which leads to a higher prevalence of latex sensitization and latex allergy symptoms [22]. In addition, Baur also confirmed a significant correlation between types of latex gloves (powdered/non-powdered) and airborne latex allergens [25]. Therefore, latex allergy was notably more prevalent in the high protein group where powdered latex gloves were still in use, highlighting the potential role of latex aeroallergen inhalation in triggering latex allergy. Our findings were consistent with many studies. Based on a study conducted in the United States, a noteworthy decrease in symptoms associated with latex glove exposure was observed, with a decline from 42 to 29% following the substitution of powdered latex gloves with non-powdered latex gloves and synthetic rubber gloves [4]. In Canada, the incidence of symptoms also decreased from 20 to 6% after those policies were implemented. Furthermore, a similar outcome was observed in Sweden, the UK, and Germany [6, 26, 27]. However, this result could be interpreted cautiously. Participants in our study may have experienced confusion between the symptoms of latex allergy and those associated with other forms of contact dermatitis. The irritant properties of powdered gloves, along with additives in latex gloves, may contribute to glove-related irritant or allergic contact dermatitis, leading to symptoms like itching and an erythematous rash, which resemble latex allergy symptoms [24, 28, 29]. This could explain the higher reporting rate of symptoms, such as itching and redness, among participants exposed to powdered latex gloves, causing some confusion. Contact dermatitis is the most common occupational skin condition and can affect individuals in various professions, including health workers [30]. A study on latex glove-related skin symptoms showed that nearly all participants (93.2%) who reported glove-related skin symptoms, such as itching, erythema, and dryness, were diagnosed with contact dermatitis, while 2.4% were confirmed to have both contact dermatitis and contact urticaria due to latex, as determined by patch tests and skin prick tests [31]. Similar results were found in a study in India, where 93.2% of participants reporting skin symptoms related to latex glove exposure had contact dermatitis, while only 28.3% were confirmed to have latex allergy, and 21.6% had both contact dermatitis and contact urticaria [32]. These findings provide evidence of potential confusion between the symptoms of latex allergy and contact dermatitis, and in some cases, both conditions may coexist.

While our study provides valuable insights, we recognize limitations. As a cross-sectional analytical study, selection bias, particularly the healthy worker effect, may be present [33]. Nursing staff with latex allergies might have left the workplace due to symptoms from latex glove exposure before data collection. However, nursing entails extensive training and expertise, making it unlikely for professionals to switch fields unnecessarily. Moreover, it’s worth noting that a previous study identified neuropsychological symptoms, such as sleep disturbances or fatigue, as the primary health concerns affecting the turnover rates of nursing staff, not allergies [34]. In addition, data from our faculty’s Occupational Health and Safety unit revealed that few nursing staff experiencing severe latex allergy symptoms, like anaphylaxis, changed careers. Hence, while the healthy worker effect may exist, its impact on our results is minimal. Furthermore, while participants were given autonomy to decide on blood collection, selection bias may still exist. Comparing variables between participants who accepted and refused blood collection revealed higher rates of underlying atopic disease, family history, surgery, and latex allergy symptoms among participants who accepted. This suggests those at higher risk of latex sensitization were more inclined to participate, potentially impacting prevalence rates. Nonetheless, upon comparing demographic data between the low and high protein exposure groups, as depicted in Table 1, there were almost no significant differences in these variables. This suggests that these risk factors may have a minimal effect on our outcome. Lastly, caution is needed when interpreting findings on latex allergy symptoms due to potential misclassification and self-report bias. However, our questionnaire underwent validation and included visuals to mitigate self-report bias.

Unlike clinical settings, the field of occupational health places a strong emphasis on proactive measures aimed at identifying abnormalities and potential health risks before they escalate into full-blown diseases. In the healthcare sector, occupational medicine physicians are pivotal in the early identification of latex sensitization. Their aim is to prevent the onset of latex allergy symptoms and minimize the risk of more severe complications among healthcare workers. Implementing personal protective equipment suitable for workers with latex sensitization is crucial to enhancing the quality of working life for health workers while simultaneously safeguarding their health. Our study suggests that one promising approach to effectively controlling and managing latex sensitization among health workers is to focus on reducing extractable protein levels in latex gloves. This approach presents a viable alternative that has the potential to contribute to the broader goal of minimizing latex-related health risks among this workforce. For instance, in settings where powdered latex gloves are still in use, tailoring the selection of latex gloves based on individual risk factors and symptoms could be a suitable approach. Health workers without risk factors or symptoms of latex allergy, considered a low-risk group, may still find powdered latex gloves with lower extractable protein levels, if available. For those experiencing mild latex allergy symptoms such as itching and/or urticaria, classified as a moderate risk group, providing non-powdered gloves with a lower protein content could be appropriate. Conversely, for individuals at a high risk of severe allergic reactions or those experiencing non-cutaneous symptoms, opting for synthetic rubber gloves and providing non-powdered latex gloves for coworkers could be the most effective strategy. This approach aligns with a previous suggestion from the UK [35] and may be implemented without significantly increasing the cost of gloves in settings where economic constraints are a concern. Additionally, while extractable protein may offer an indirect measurement of latex glove allergenicity compared to other techniques, such as determining latex allergen levels, it is more practical and cost-effective. This makes it feasible to assess protein levels in latex gloves in many settings, especially in developing countries where resources may be limited. By addressing the root cause of latex sensitization and taking proactive steps, such as assessing and replacing gloves with high protein levels with lower ones, we can ensure the well-being and longevity of healthcare professionals in their critical roles within the healthcare industry.

Future studies should delve into the potential factors stemming from the observed extractable protein levels in both the high and low protein groups. Unlike previous studies, where powdered latex gloves typically exhibited higher extractable protein levels, our findings show a closer resemblance in protein levels between the two groups. Thus, further investigation is needed to understand the implications of these protein levels, especially in populations exposed to higher concentrations (> 200 µg/g) in latex gloves. Moreover, comprehensive clinical assessments in future studies can help distinguish true latex allergy from other dermatological reactions, providing a clearer understanding of how glove type influences symptom presentation among healthcare workers.