2.1. Study design and sample size calculation
This study was approved by the Istanbul Aydin University Clinical
Research Ethics Committee with B.30.2.AYD.0.00.00-480.2/217 protocol
number before the research. The statistical power analysis was showed
that a minimum sample of n=73 in each group would have the assumption of
95% CI and power of 80%. A nominal α=0.05 and two-tailed tests were
used in the power calculations.
We recruited a total of 117 schizophrenia patients aged 18 – 65 years
as a case group. For each schizophrenia patient, one healthy control
people were recruited. Individuals in the control group were randomly
selected from the city where the patients lived (Istanbul, Turkey) and
matched for age (± 3 years) and gender. The workflow diagram clarifies
the design of this case-control study (Fig 1).