Varying where in the sentence an adverbial is placed is an effective way of making the sentence structure less repetitive, thus making the text more interesting to read. Here, the adverbial can be found at the beginning of the sentence, rather than towards the end. By placing it at the beginning of the sentence, the author makes the topic/setting of the sentence clear from the start, which is helpful for the reader.

In the present study, socioeconomic status did not appear to confound the results.

Compare:

Socioeconomic status did not appear to confound the results in the present study.