INS and diabetes mellitus: Thirty-four studies measured diabetes as a health outcome, using either prevalence/incidence of diabetes (n = 31) [29–32, 39, 41–43, 45–52, 55–61, 65, 68, 69, 73, 75, 77, 80], glycaemic control (n = 2) [44, 82] and insulin resistance (n = 1) [66].