Table 2. Summary of the studies analyzed.

No. of studies a	31
No. of trials b	23
Sample size of the trials b	4395
Percentage of female participants b	41
Age of participants (yr) b	57.9
Percentage of participants with diabetes b	45
Body mass index (kg/m2) b	26.8
Percent of current smoking (%) b	15.6
Cause of ESRD b :
Hypertension (%)	26.5
Diabetes mellitus (%)	41.6
Glomerulonephritis (%)	14.1
Polycystic kidney (%)	4.0
Other (%)	13.8

^a All studies having been analyzed are included

^b The same data were extracted for only once