While this study is not considered conclusive in linking high intake of vitamin A to increased risk of osteoporosis, the developing body of research is leading some experts to advise consumers to be more vigilant about abiding by federal intake guidelines for vitamin A and the degree to which foods fortified with it can increase risk of poor bone health.

The study is considered limited partly because it measured levels of A in the blood but did not gather information about the subjects' diets. Some experts believe that the body, which stores vitamin A in fat, keeps blood levels of retinol fairly constant regardless of dietary intake. If that's the case, this study can connect only high blood A levels with fractures, but not high intake of dietary or supplemental A to those fracturers.

Robert Russell, professor of medicine and nutrition at Tufts University School of Medicine and chair of the panel that wrote the recent IOM report on vitamin A, says high serum retinol levels may have some connection to bone fragility, but he questions the trend toward believing vitamin A in the diet leads to broken bones.