1. Newcastle University; Institute for Ageing and Institute of Health and Society; Baddiley-Clark Building Newcastle upon Tyne UK NE2 4AX
2. Newcastle University; Institute of Health and Society; Baddiley-Clark Building Richardson Road Newcastle upon Tyne UK NE2 4AX
3. King's College London; Health Service and Population Research; De Crespigny Park London UK SE22 0HP
4. Fondazione "Università G. D'Annunzio"; Centre for Systematic Reviews; Via dei Vestini 31 Chieti Chieti Italy 66100
5. University of Bern; Institute of Social and Preventive Medicine (ISPM); Finkenhubelweg 11 Bern Bern Switzerland 3012
6. Newcastle University; Human Nutrition Research Centre, Institute for Ageing and Health; Campus of Ageing and Vitality Newcastle University Newcastle upon Tyne UK NE4 5PL