Association of diabetes and obesity with sperm parameters and testosterone levels: a meta-analysis
Bibliographic record
Abstract
Abstract Background The present study performed two distinct meta-analyses with common outcomes (sperm parameters); one was performed in obese individuals (and non-obese controls) and the other in diabetic individuals (and non-diabetic controls). Methods PubMed, Embase, The Cochrane library, Web of Science, Scopus databases were searched to collect clinical studies related to the effects of obesity and diabetes on male sperm from inception to on 1st February 2021. Statistical meta-analyses were performed using the RevMan 5.4 software. Stata16 software was used to detect publication bias. The methodological quality of the included studies was assessed with the Ottawa–Newcastle scale using a star-based system. Results A total of 44 studies were finally included in the present study, which enrolled 20,367 obese patients and 1386 patients with diabetes. The meta-analysis results showed that both obesity and diabetes were associated with reduced semen volume (obese versus non-obese controls: mean difference (MD) = − 0.25, 95% CI = (− 0.33, − 0.16), p < 0.001; diabetes versus non-diabetic controls: MD = − 0.45, 95% CI = (− 0.63, − 0.27), p < 0.001), reduced sperm count (obese versus non-obese controls: MD = − 23.84, 95% CI = (− 30.36, − 17.33), p < 0.001; diabetes versus non-diabetic controls: MD = − 13.12, 95% CI = (− 18.43, − 7.82), p < 0.001), reduced sperm concentration (obese versus non-obese controls: MD = − 7.26, 95% CI = (− 10.07, − 4.46), p < 0.001; diabetes versus non-diabetic controls: MD = − 11.73, 95% CI = (− 21.44, − 2.01), p = 0.02), reduced progressive motility (obese versus non-obese controls: MD = − 5.68, 95% CI = (− 8.79, − 2.56), p < 0.001; diabetes versus non-diabetic controls: MD = − 14.37, 95% CI = (− 21.79, − 6.96), p = 0.001), and decreased testosterone levels (obese versus non-obese controls: MD = − 1.11, 95% CI = (− 1.92, − 0.30), p = 0.007; diabetes versus non-diabetic controls: MD = − 0.37, 95% CI = (− 0.63, − 0.12), p = 0.004). Conclusions Current evidence suggests that obesity and diabetes negatively affect sperm parameters in men and are associated with low testosterone levels. Due to the limitation of the number and quality of included studies, the above conclusions need to be verified by more high-quality studies.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.331 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".