John Hart MHS, DC
Journal of Vertebral Subluxation Research. July 2, 2008
Introduction: A previous study found that chiropractor ratios were more strongly correlated with improved health outcomes in the U.S., for years 2001-2005, compared to physician (medical and osteopathic) ratios. This study seeks to determine if such correlations exist for an earlier year (1995). The variables of income, education and health insurance coverage were also assessed in relation to the health outcomes.
Methods: The following variables, considered as determinants having a possible effect on mortality rates, were obtained for the 50 states and District of Columbia for the year 1995: Ratios for chiropractors and physicians (medical doctors), percent of persons below poverty level, median income, personal per capita income, health insurance, and educational attainment (high school diploma or higher, and bachelor degree or higher). Mortality rates for the top three causes of death in 1995 were obtained as follows: Heart disease, cancer, and cerebrovascular disease. Mortality rate from all causes was also included. Correlations were performed between the determinants and mortality rates using the Spearman correlation test.
Results: Increased median income showed the strongest correlation with reduced mortality rates (from all causes, r = -0.480, p = 0.000). Between chiropractor and medical doctor ratios, chiropractors showed stronger correlations for reduced mortality rates for cancer (r = -0.378, p = 0.007), heart disease (r = -0.344, p = 0.01), and all causes (r = -0.402, p = 0.004). Medical doctor ratios showed a stronger correlation with reduced cerebrovascular mortality (r = -0.259, p = 0.07) compared to chiropractor ratios.
Discussion: Determinants of median income, educational attainment and chiropractor ratios were more strongly correlated with decreased mortality compared to determinants of health insurance or medical doctor ratios.
Conclusion: Correlation does not necessarily show causation but it can provide clues. Increases in median income, educational attainment, and chiropractor ratios were most strongly correlated with reduced (improved) mortality rates. Health insurance coverage and medical doctor ratios showed the least correlation with reduced mortality rates.
Key Words: Chiropractic, chiropractor ratios, physician ratios, mortality rates, heart disease, cancer, cerebrovascular