Some studies reported no association [ 40 , 43 , 47 ], others showed a possible trend towards a positive association [ 13 , 26 ], and other studies found an inverse association [ 41 , 42 , 44 ].
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Some studies reported no association [ 40 , 43 , 47 ], others showed a possible trend towards a positive association [ 13 , 26 ], and other studies found an inverse association [ 41 , 42 , 44 ].