Table 1.
Characteristics of Studies Included in the Meta‐analysis
| First Author and Year | Location | Study Design | Patients With AF/Total Patients, N | Definition of AF | Methods of AF Detection | Measurement of Vitamin D | Winter or Spring Season | Definition of Vitamin D Deficiency | Follow‐up | Quality Score |
|---|---|---|---|---|---|---|---|---|---|---|
| Rienstra 2011 | United States | Prospective cohort | 425/2930 | New‐onset AF | ECGs (clinic visits, external physician visits, Holter monitoring, or hospital records) | A competitive protein‐binding assay (Original cohort) and a radioimmunoassay (Offspring cohort) | 1160 (winter) | 25(OH)D <17 ng/mL for the Original cohort and 13.4 ng/mL for the Offspring cohort | 9.9 ± 4.0 years | 8 |
| Chen 2014 | China | Case control | 162/322 | Nonvalvular persistent AF | ECG | Chemiluminescence assay | 322 (spring) | <20 ng/mL | NA | 8 |
| Demir 2014 | Turkey | Case control | 102/202 | Nonvalvular persistent AF | NA | Electrochemiluminescence method | 202 (winter) | NA | NA | 8 |
| Ozcan 2015 | Turkey | Case control | 137/227 | New‐onset AF | ECG or ambulatory Holter monitoring | Chemiluminescent immunoassay | 227 (winter and spring) | <20 ng/mL | NA | 8 |
| Vitezova 2015 | Netherlands | Prospective cohort | 263/3395 | New‐onset AF | ECG | Electrochemiluminescence immunoassay | NA | <50 nmol/L (20 ng/mL) | 12.0 years | 8 |
| Mathew 2014 (MESA/CHS) | United States | Prospective cohort | 291/6398, 229/1350 | New‐onset AF | Systematic reviews of hospital discharge diagnoses, inpatient and outpatient physician claims data, and study ECGs | Mass spectrometry | NA | NA | 7.7 years, 8.0 years | 8, 8 |
| Alonso 2016 | United States | Prospective cohort | 1866/12 303 | New‐onset AF | ECGs performed during study examinations, hospital discharge codes, and death certificates | Mass spectrometry | NA | <20 ng/mL | 21 years | 9 |
| Belen 2016 | Turkey | Case control | 96/180 | Chronic AF | NA | High‐performance liquid chromatography | All were examined at similar seasonal periods | NA | NA | 8 |
Abbreviations: AF, atrial fibrillation; CHS, Cardiovascular Health Study; ECG, electrocardiogram; MESA, Multi‐Ethnic Study of Atherosclerosis; NA, not applicable.