Immunization status of adult chiropractic patients in analyses of national health interview survey.

OBJECTIVE: Two recent studies that examined National Health Interview Survey data reported divergent findings regarding the propensity of adult chiropractic users to receive seasonal influenza immunization. Although one study found a statistically significant negative association between chiropractic use and influenza vaccination, another found that chiropractic users were significantly more likely to be vaccinated. The purpose of this study is to extend previous works by delving more deeply into recent data to identify adult chiropractic users at high risk and high priority for vaccination against influenza and pneumococcal disease.
METHODS: We used data from the 2007 National Health Interview Survey in an attempt to replicate previous methodologies and further examine vaccination among adult chiropractic users (age ≥18 years) who, according to the Center for Disease Control and Prevention guidelines, should receive influenza and/or pneumococcal vaccination. We used complex survey design methods to make national estimates and used logistic regression to determine if having used chiropractic care predicted vaccination.
RESULTS: We found major methodological differences between the prior studies. In our analyses, we found that chiropractic users were significantly less likely than nonusers to have received the pneumococcal vaccine, and we found no significant difference between chiropractic users and nonusers relative to having received the seasonal flu vaccine.
CONCLUSIONS: Methodological differences in previous studies that investigated the association between chiropractic care and adult vaccination likely explain divergent findings reported in the literature. Future studies should consider these differences.