Table 2. Meta-analyses of observational studies (prospective and cross-sectional studies): the effects of total-, free-, and bioavailable-testosterone on CVD events are presented as beneficial (friendly)*, detrimental (a foe)† or no effects at all (bystander)‡ in terms of their magnitude of association and statistical significance.
| Study author and year | Study design | Number of studies for meta-analyses | Number of participants (n) | Exposure (high levels vs. low levels or continuous increment 1 S.D.) | Cardiovascular events (n) | Results: only fully-adjusted multivariable models | SS (P<0.05) or NS |
|---|---|---|---|---|---|---|---|
| Beneficial (friendly) effects* | OR’s, RR’s or HR’s that are lower or equal to 0.90 | ||||||
| Corona et al., 2011 (29) | Meta-analyses of cross-sectional studies | 54 | 5,153 CVD patients and 7,513 non-CVD | Total testosterone, nmol/L; (continuous increment 1 S.D.) | CVD events (n=5,153) | HR =0.53; 95% CI, 0.44–0.60 | SS (P<0.0001) |
| Araujo et al., 2011 (30)a | Meta-analyses of prospective and cross-sectional studies | 7 | 11,831 | Total testosterone, ng/dL (high tertile vs. low tertile) | CVD mortality (n=n/a) | HR =0.80 | NS |
| Ruige et al., 2011 (31) | Meta-analyses of prospective and nested-case control study | 18 | n/pb | Total testosterone, nmol/L (continuous increment 1 S.D.) | CVD events (n=4,598) | RR =0.89; 95% CI, 0.83–0.96 | SS |
| 7 | n/pb | Free testosterone, nmol/L. (continuous increment 1 S.D.) | CVD events (n=1,709) | RR =0.88; 95% CI, 0.78–1.00 | NS | ||
| 3 (men >70 years) | n/pb | Bioavailable testosterone, nmol/L; (continuous increment 1 S.D.) | CVD events (n=692) | RR =0.74; 95% CI, 0.62–0.88 | SS | ||
*, beneficial (friendly) effects is the magnitude of association such as odd ratios (OR’s), rate ratios (RR’s), or hazard ratios (HR’s) whether they are below or equal to 0.90; †, detrimental (foe) effects if the OR’s, RR’s or HR’s are greater or equal to 1.10; ‡, no effects at all (bystander) if it is neither friendly nor foe; a, Araujo—we used the reciprocal of CVD from the comparison of low testosterone vs. high testosterone to show the risk of CVD by comparing high vs. low tertile of testosterone levels; b, not provided data; SS, statistically significant; NS, not statistically significant; CVD, cardiovascular disease.