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| Block 5: Epidemiology Exercise |
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A CASE STUDIES ON LATEX ALLERGY:
PART A:
Read the abstract below. Answer the questions using clues from the abstract and the table provided.
ABSTRACT:
Objective:
To determine the occurrence of latex sensitisation among a large group of healthcare workers, to study the occupational and non-occupational factors associated with latex allergy, and to characterise latex exposure in air and by gloves.
Methods:
All 2062 employees of a general hospital in Hamilton, Ontario, Canada who regularly used latex gloves were invited to participate in a survey, representing the baseline phase of a prospective cohort morbidity study. Attempts were made to recruit employees who were diagnosed with latex allergy before the survey. Glove extracts were assayed for antigenic protein, and area and personal air samples were obtained on two occasions (summer and winter) to estimate exposure to airborne latex protein. A questionnaire on medical and occupational information was administered by an interviewer. Skin prick tests were performed with latex reagents, three common inhalants, and six foods.
Results:
The mean (SD) latex protein concentrations were 324 (227) micrograms/g in powdered surgical gloves and 198 (104) micrograms/g in powdered examination gloves. Personal latex aeroallergen concentrations ranged from 5 to 616 ng/m>sup>3. There was a total of 1351 (66%) participants.
| Characteristic | Latex SPT positive n (% positive) |
Latex SPT negative n (% negative) |
|---|---|---|
| All (n = 1326) | 160 (12.1) | |
| Age group | ||
| <30 (264) | 23 (8.7) | |
| 30 - 39 (447) | 53 (11.9) | |
| 40 - 49 (358) | 47 (13.1) | |
| > 49 (211) | 23 (10.9) | |
| Total known (1280) | 146 (11.4) | |
| Sex | ||
| 1208 Female | 148 (12.3) | |
| 108 Male | 12 (11.1) | |
| Atopy | ||
| Yes (138) | 61 (44.2) | |
| No (1187) | 99 (8.3) | |
| Smoking | ||
| Ever smoked | ||
| Yes (138) | 72 (11.3) | |
| No (1187) | 99 (12.8) | |
| Smoking status | ||
| Current (269) | 26 (9.7) | |
| Ex (370) | 46 (12.4) | |
| Never (687) | 88 (12.8) | |
| Job title | ||
| Lab workers (65) | 11 (16.9) | |
| Nurses and physicians (788) | 105 (13.3) | |
| Housekeepers (78) | 9 (11.5) | |
| Therapists and technicians (145) | 11 (7.6) | |
| Other (231) | 22 (9.5) | |
| Gloves per day over past 3 days | Latex SPT positive Mean number |
Latex SPT negative Mean number |
| Total | 9.4 | 9.5 |
| Latex | 5.4 | 6.6 |
| Vinyl | 4.0 | 2.9 |
| Hand contact (%>1 week) with: | Percentage | Percentage |
| Formaldehyde | 3.1 | 3.1 |
| Glutaraldehyde | 1.3 | 2.3 |
| Bleachers | 11.3 | 16.6 |
| Cleaners | 22.5 | 22.4 |
Question #1:
What sort of study is this?
Question #2:
The occurrence of positive latex skin tests was ___
Question #3:
What is this measure of occurrence called?
Question #4:
This occurrence varied by:
- Sex: Yes/No
- Age: Yes/No
- Smoking status: Yes/No
- Atopic status: Yes/No
- Job title: Yes/No
- Glove use: Yes/No
- Contact with dermal irritants: Yes/No
Participants who were latex positive were significantly more likely to have positive skin tests to one or more foods (Mantel-Haenszel odds ratio (OR) adjusted for atopy 12.1, 95% CI 7.6 to 19.6, P < 10(-9)). Work related symptoms were more often reported among latex positive people, and included hives (OR 6.3, 95% CI 3.2 to 12.5), eye symptoms (OR 1.9, 95% CI 1.2 to 2.8), and wheezy or whistling chest (OR 4.7, 95% CI 2.8 to 7.9).
We can draw some conclusions from this.
Question #5:
In this large study of healthcare workers in a hospital setting, the minimum estimate of the occurrence of latex sensitisation among all those eligible was ___.
Question #6:
What makes this a large study?
The intention is to continue the study in future to determine the occurrence of development of latex sensitivity.
Question #7:
What sort of future study is being planned?
Question #8:
Name a measure of occurrence they could use in the future study.
Question #9:
Who will be enrolled into the new study?
General Introduction to Occupational Health: Occupational Hygiene, Epidemiology & Biostatistics by Prof Jonny Myers is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 South Africa License