A systematic evaluation of the available evidence suggests similarities as well as important differences in the risk factors for incidence of AF as compared with other cardiovascular diseases , which has implication s for the primary prevention strategies for atrial fibrillation
Established primary prevention strategies of cardiovascular diseases are based on underst and ing of risk factors , but whether the same risk factors are associated with  atrial fibrillation ( AF )  remains unclear .
Normal Thyroid Function and the Risk of Atrial Fibrillation: the Rotterdam Study.
CONTEXT Hyperthyroidism is an established risk factor for atrial fibrillation ( AF ) , but information concerning the association with variations within the normal range of thyroid function and subgroups at risk is lacking . OBJECTIVE This study aim ed to investigate the association between normal thyroid function and AF prospect ively and explore potential differential risk patterns . DESIGN , SETTING , AND PARTICIPANTS From the Rotterdam Study we included 9166 participants ≥ 45 y with TSH and /or free T4 ( FT4 ) measurements and AF assessment  ( 1997 - 2012 median followup , 6.8 y ) , with 399 prevalent and 403 incident AF cases . MAIN OUTCOME MEASURES Outcome measures were 3-fold : 1 ) hazard ratios ( HRs ) for the risk of incident AF by Cox proportional-hazards models , 2 ) 10-year absolute risks taking competing risk of death into account , and 3 ) discrimination ability of adding FT4 to the CHARGE-AF simple model , an established prediction model for AF . RESULTS Higher FT4 levels were associated with higher risks of AF ( HR 1.63 , 95 % confidence interval , 1.19 - 2.22 ) , when comparing those in the highest quartile to those in lowest quartile . Absolute 10-year risks increased with higher FT4 in participants ≤ 65 y from 1 - 9 % and from 6 - 12 % in subjects ≥ 65 y. Discrimination of the prediction model improved when adding FT4 to the simple model ( c-statistic , 0.722 vs 0.729 ; P = .039 ) . TSH levels were not associated with AF . CONCLUSIONS There is an increased risk of AF with higher FT4 levels within the normal range , especially in younger subjects . Adding FT4 to the simple model slightly improved discrimination of risk prediction
A systematic evaluation of the available evidence suggests similarities as well as important differences in the risk factors for incidence of AF as compared with other cardiovascular diseases , which has implication s for the primary prevention strategies for atrial fibrillation
Established primary prevention strategies of cardiovascular diseases are based on underst and ing of risk factors , but whether the same risk factors are associated with  atrial fibrillation ( AF )  remains unclear .