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Ida said, > When one tells people that one has reason to think PD and diabetes have some > common cause (and hence can be expected to be present in the same persons > or families) and then asks those people to report whether this is or is not in > accordance with their own situation, you can expect relatively more reactions > from people who recognise this is the case for them then from others. This > makes that the resulting numbers are not a base to draw any conclusion from. Sad to say, Ida, but you are so right. Also, in order to pass peer review, at least in Australia, a research project should have more or less equal numbers of affected and non-affected subjects, of roughly the same demographics (ie, similar geographic location, economic circumstances, age, sex, etc.) The questions should be unambiguous, and should not be capable of being misinterpreted. In this case, that could mean making it very clear to the subject that only blood relatives were of interest. Further questions would need to be asked to eliminate (hopefully) alternative explanations for an observation. Negative answers would need to be differentiated from lack of an answer. Finally, a sample size less than one hundred is not really statistically relevant. That means a total survey of two hundred when the non-affected subjects are added. Theories extrapolated from smaller sample bases must be treated with caution. Better still would be a sample size of 1000 + 1000 = 2000. How depressing that is to unfunded, unassisted people pursuing an idea. But even so, Ivan is to be congratulated for expending the time and effort to carry out his survey, and the survey does have value, in that it suggests a possible line of research for someone with resources. I am reporting his results to our research group, as background material to interpreting our own data. So, if anyone out there has time on their hands, and a promising idea, go for it. We can't know too much about PD. Jim