A word of caution about relying on research studies more than 5 years ago. Medical research is usually 2-3 years behind by the time of its publication date. The rule of thumb is not to cite research that is more than 5 years old. Regarding a negative association between osteoarthritis and osteoporosis there is more current literature that challenges that assumption by gender specific studies. Contemporary research demonstrates these conditions in men are non-linear and lean heavily on diagnostic parameters. The studies demonstrate a shifting from a positive association in mild disease to a high co-occurrence of OP in end stage severe OA. Studies can be found on PubMed Central.