In a case-control study of exercise as a protective factor against development of osteoporosis, people with disease (cases) tended to overestimate their level of exercise more than the control subjects. The likely effect of these overestimates on any observed relationship between the two variables is:

to shift the odds ration magnitude toward the value of 1.0.

Explanation:

The case-control study may be defined as the type of study which helps determining whether an exposure( a condition of interests or a disease) is associated with a relevant outcome or not. Here two groups that differs in their outcomes are identified and are compared to basis of supposed causal attributes.

In the context, a case-control study where exercise which is considered as a protective factor in case of osteoporosis, people having the osteoporosis are tended more to overestimate the level of their exercise much more than their control subjects. The effects of these overestimates of the observations is to shift the odds ration magnitude toward the value of 1.0.