Volume 13, Number 7—July 2007
Dispatch
Zinc Cream and Reliability of Tuberculosis Skin Testing
Table
Population characteristics for the participants who had simultaneous skin tests with and without zinc and associations with size of tuberculosis (TB) skin-test reaction
| Characteristic* | Mean (SEM)† or % (n = 50) | Association with size of control TB skin-test reaction (mm) |
|||
|---|---|---|---|---|---|
| Univariate analysis |
Multiple regression |
||||
| Coefficient | p | Coefficient | p | ||
| Nutritional assessmentठ| |||||
| Body mass index (kg/m2) | 24 (0.52) 10% underweight (<20) | 0.2 | 0.3 | ||
| Anthropometric protein status (corrected arm muscle area; cm2) | 36 (1.4) | 0.2 | 0.09 | ||
| Anthropometric fat status (arm fat area; cm2) | 14 (1.1) | 0.0008 | 1 | ||
| Plasma zinc (mg/L; n = 49) | 0.66 (0.17) 31% deficient (<0.6) | 0.3 | 0.04 | 0.3 | 0.03 |
| Minor incidental health symptoms | 38% | 0.06 | 0.7 | ||
| TB risk factors | |||||
| Age, y | 32 (1.3) | 0.2 | 0.2 | 0.3 | 0.02 |
| Male | 38% | 0.3 | 0.03 | 0.4 | 0.01 |
| Past close contact with a TB patient or past proven diagnosis of TB | 42% | 0.1 | 0.4 | ||
| Presence of Baccilus Calmette-Guérin vaccine scar(s) | 86% | 0.2 | 0.3 | ||
| Overcrowding (persons/room) | 1.3 (0.08) | –0.2 | 0.9 | 0.2 | 0.09 |
| Poor household ventilation (subjective assessment) | 24% | –0.002 | 1 | ||
| Socioeconomic status | |||||
| Food spending/person/d ($US) | 0.75 (0.05) | 0.1 | 0.5 | ||
| Dirt floor throughout the home | 38% | –0.06 | 0.7 | ||
| Home built from temporary materials | 72% | 0.1 | 0.5 | ||
| No in-house sanitation | 84% | 0.05 | 0.7 | ||
| No piped water to home | 84% | –0.07 | 0.6 | ||
*Variables that may influence TB skin-test reaction size are shown together with their associations with the size of the control TB skin-test reactions associated with only zinc cream application.
†SEM, standard error of the mean.
‡Food frequencies: in the previous week, alcohol had been consumed a median of 1 time (median 1 U), dairy produce 3 times, fruit/vegetables 5 times, meat/fish 6 times, and rice/bread/cereals daily.
§Persons with infrequent meat/fish consumption had lower protein stores on muscle anthropometry (p = 0.02), and this tended to be associated with smaller skin-test reactions, as previously reported (1,2).
