Correction

Dai Q, Shu X-O, Deng X, et al. Modifying effect of calcium/magnesium intake ratio and mortality: a population-based cohort study. BMJ Open 2013; 3 :e002111. The column headings in tables 1？？？–5 have shifted, resulting in incorrectly labelled column headers. View this table: Table？1 Baseline lifestyle factors and demographics by intakes of calcium and magnesium, the Shanghai Women's Health Study (SWHS) and the Shanghai Men Health Study (SMHS), 1996–2009 View this table: Table？2 HRs and 95% Confidence Intervals (95% CIs) for total mortality, and mortality due