Table 2.

NHLBI quality assessment tool for observational cohort and cross-sectional studies.

Criteria	Agac et al. [32]	Boddi et al. [33]	Dunn et al. [34]	Ravichandran et al. [35]	Emre et al. [36]	Kocharyan [37]	Ozturk et al. [38]	Perera et al. [39]	Keskin et al. [40]	Olubunmi et al. [41]	Alexander et al. [42]	Kim et al. [43]	Labenz et al. [44]	Montemezzo et al. [45]	Sinn et al. [46]	Vandromme et al. [47]	Xia et al. [48]
(1) Was the research question or objective in this paper clearly stated?	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
(2) Was the study population clearly specified and defined?	No	Yes	Yes	Yes	No	Yes	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes
(3) Was the participation rate of eligible persons at least 50%?	NR	Yes	Yes	NR	Yes	NR	NR	Yes	NR	Yes	Yes	Yes	Yes	NR	Yes	NR	NR
(4) Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants?	CD	Yes	Yes	Yes	Yes	Yes	NR	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	Yes
(5) Was a sample size justification, power description, or variance and effect estimates provided?	No	Yes	No	No	No	No	No	No	No	No	No	No	No	Yes	No	No	Yes
(6) For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured?	No	No	No	No	No	No	No	No	No	Yes	Yes	Yes	Yes	No	Yes	No	No
(7) Was the time frame sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed?	No	No	Yes	No	No	No	No	No	No	Yes	Yes	Yes	Yes	No	Yes	No	No
(8) For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)?	Yes	Yes	Yes	Yes	Yes	No	Yes	No	Yes	Yes	No	Yes	No	Yes	No	No	No
(9) Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
(10) Was the exposure(s) assessed more than once over time?	No	No	Partially (81 subjects)	No	No	No	No	No	No	No	No	No	No	No	No	No	No
(11) Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
(12) Were the outcome assessors blinded to the exposure status of participants?	Yes	Yes	NR	CD	NR	NR	Yes	NR	NR	NR	NA	NA	NA	Yes	NA	NA	NR
(13) Was loss to follow-up after baseline 20% or less?	NA	NA	NA	NA	Yes	Yes	NA	NA	NA	Yes	NA	NA	NA	NA	NA	NA	NA
(14) Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)?	Yes	Yes	Yes	Yes	Yes	No	No	Yes	Yes	Yes	Yes	Yes	Yes	No	No	No	Yes
Rating	Fair	Good	Good	Fair	Good	Fair	Poor	Fair	Fair	Good	Good	Good	Good	Fair	Fair	Poor	Fair