<prompt> Translate the following text to EnglishIngawa utaratibu wa kibiolojia kwa ajili ya athari hii bado haijaanzishwa kwa uhakika, uzito wa ushahidi wa magonjwa ya kuambukiza inasaidia dhana ya sababu.  <response>: While biological mechanisms for this effect have not yet been definitively established, the weight of the available epidemiological evidence supports an assumption of causality. 