Clustered metabolic risk and leisure-time physical activity in adolescents: effect of dose? - Pahkala, K; Heinonen, O J; Lagström, H; Hakala, P; Hakanen, M; Hernelahti, M; Ruottinen, S; Sillanmäki, L; Rönnemaa, T; Viikari, J; Raitakari, O T; Simell, O (Br J Sports Med, 2012)