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Matched controls in a case-control study. Does matching by doctor's list mean matching by relative deprivation?

In case-control studies it is important that controls selected are representative of the population from which the cases came, to give an unbiased estimate of population exposure. This is difficult to achieve, but one method to select controls has been to use the patient lists of the general practitioners with whom the cases are registered. Using data from a case-control study of heart attacks in young women; this article explores whether this method of selecting controls resulted in an unrepresentative distribution of deprivation levels in controls. The controls did not reflect the high levels of deprivation seen in the cases, although they came from the same neighbourhoods (general practice catchment areas). Such controls are often referred to as neighbourhood controls, but this is misleading. General practice controls are more likely to represent the general distribution of the population than the relative affluence or otherwise of the cases.