Table 5.
Studies on postnatal endocrine disrupting chemical exposure and associations with semen quality.
| EDC class | Reference | matrix | Study design | Chemicals/congeners reported | n of subjects | Country | Association between chemical levels and semen quality |
|---|---|---|---|---|---|---|---|
| Phenols: BPA | |||||||
| Adoamnei 2018 | (164) | Urine | Cross-sectional | BPA | 215 university students | Spain | Negative association with sperm concentration and TSC |
| (age range, 18–23 y) | |||||||
| Caporossi 2020 | (165) | Urine | Cross-sectional | BPA | 155 male partners of subfertile couples, aged 40.5 y | Italy | Positive association between BPA level and semen volume |
| Ji 2018 | (166) | Urine | Cross-sectional | BPA | 500 fertile men, aged 18-55 y | China | Negative association with sperm concentration and sperm swing characteristics and positive association with sperm velocity ratios. |
| Kranvogl 2014 | (167) | urine | Cross-sectional | BPA | 136 male partners of infertile couples (mean age, 36.2 y) | Slovenia | No association between BPA and sperm concentration or sperm motility |
| Meeker 2010 | (168) | Urine | Cross-sectional | BPA | 190 men attending infertility clinic | USA | Negative association with sperm concentration, motility and morphology |
| Mean age, 37 y | |||||||
| Mendiola 2010 | (169) | Urine | Cross-sectional | BPA | 302 fertile men | USA | NS |
| Mean age, 31.9 y | |||||||
| Li 2011 | (170) | Urine | Cohort | BPA | 218 men with and without occupational BPA exposure | China | Negative association with sperm concentration, TSC and sperm motility |
| (age from <25 to > 45y) | |||||||
| Knez 2014 | (171) | Urine | Cohort | BPA | 149 male partners of couples undergoing IVF | Slovenia | Negative association with sperm concentration and TSC |
| (mean age, 34 y) | |||||||
| Lassen 2014 | (172) | Urine | Cross-sectional | BPA | 308 young men from general population | Denmark | Men in the highest quartile of BPA had significantly lower % progressive motile spermatozoa vs men in the lowest quartile |
| No association with other semen parameters | |||||||
| Goldstone 2015 | (173) | Urine | Cohort | BPA | 418 male partners of couples trying to conceive | USA | NS |
| (mean age, 31.7 y) | |||||||
| Hu 2017 | (174) | Urine | Cross-sectional | BPA | 357 subfertile men | China | NS |
| (mean age, 28.7 y) | Among obese men, negative association with sperm concentrations and total sperm counts | ||||||
| Omran 2018 | (175) | Urine | Case-control | BPA | 50 infertile men and 50 controls | Egypt | urinary BPA levels did not differ between infertile men and controls. |
| All participants: urinary BPA levels: positive association with percentage of abnormal sperm morphology | |||||||
| Negative association with progressive sperm motility and total sperm counts | |||||||
| Pollard 2019 | (176) | Urine | Cross-sectional | BPA | 161 men, aged 18-40 y with unknown subfertility | USA | Men with abnormal sperm tail morphology had higher geometric mean of BPA exposure than men with normal sperm morphology |
| Radwan 2018 | (177) | Urine | Cross-sectional | BPA | 315 men, aged <45 y, who had sperm concentration of ≥ 15 million/ml | Poland | Negative association with sperm motility |
| Vitku 2015 | (178) | Plasma seminal fluid | Cross-sectional | BPA | 174 men attending the fertility center | Czech Republic | Slightly infertile men had higher BPA levels in plasma and seminal plasma as compared with healthy men. |
| Mean age, 36 y | Negative association between seminal BPA level (but not plasma BPA) and sperm concentration and TSC | ||||||
| Vitku 2016 | (179) | Plasma and Seminal plasma | Cross-sectional | BPA | 191 men attending infertility clinic | Czech Republic | Plasma BPA: NS |
| Mean age, 36 y | Seminal plasma BPA: negative association with sperm concentration, TSC and normal sperm morphology. | ||||||
| Phenols: Bisphenol S (BPS) | |||||||
| Ghayda 2019 | (180) | Urine | Cross-sectional | BPS | 158 men attending fertility center | USA | Men with detectable vs non-detectable BPS levels had lower semen volume, sperm concentrations, TSC and %morphologically normal sperm |
| (age 18-56 y) | |||||||
| Parabens | |||||||
| Adoamnei 2018 | (181) | Urine | Cross-sectional | BP | 215 university students, aged 18-23 y | Spain | NS |
| EP | |||||||
| MP | |||||||
| PP | |||||||
| Jurewicz 2017 | (56) | Urine | Cross-sectional | BP EP iBuP MP PP |
315 men aged less than 45 y who attended the infertility clinic with normal semen concentration (15-300 million/mL) | Poland | Positive association with %sperm with abnormal morphology Negative association with %motility |
| Meeker 2011 | (182) | Urine | Cross-sectional | Parabens | 190 male partners attending infertility clinic who had semen analysis results | USA | NS |
| Mean age, 36.7 y | |||||||
| Smarr 2018 | (183) | Urine | Cross-sectional | MP EP PP BP BzP HP 4-HB 3,4 DHB OH-MeP OH-EtP |
501 male partners of couples planning to become pregnant Mean age = 31.8 y |
USA | Negative association between EP, BP levels and sperm count Negative association between EP, MP levels and % sperm motility Negative association between BP level and CASA sperm motility parameters (average path velocity, straight-line velocity, curvilinear velocity, beat cross frequency, %straightness and %linearity) Positive association between OH-MeP level and %normal sperm (by WHO criteria) Positive association between OHEtP level and %normal sperm (by Strict and WHO criteria) |
| Phthalates | |||||||
| Albert 2018 | (184) | Urine | Cross-sectional | Phthalate metabolites | 153 healthy men, aged 18-41 y | Canada | NS |
| Axelsson 2015 | (185) | Urine | Cross-sectional | 10 phthalate metabolites | 314 men from general population, aged 17-20 y | Sweden | Negative association between all the DEHP metabolites (MEHP, MECPP, MEOHP, MEHHP, MBP) and progressive sperm motility |
| Positive association of MCiOP, % MEHP with semen volume | |||||||
| Chang 2017 | (186) | Urine and seminal fluid | Cross-sectional | Phthalate metabolites | 253 male partners of subfertile couples | Taiwan | Urinary phthalate metabolites |
| Negative associations between: | |||||||
| 37 male partners of fertile couples | - MBzP, MEHP, MEHPX and sperm concentration | ||||||
| Mean age: 33 y | - MBzP, MEHP and sperm motility | ||||||
| Seminal phthalate metabolites | |||||||
| Negative association between | |||||||
| - MEHP and mono-2-ethyl-5-hydroxyhexyl phthalates and sperm concentration | |||||||
| - MEP, DEHP metabolites and sperm motility | |||||||
| - MEP and morphologically normal sperm | |||||||
| Chen 2017 | (187) | Urine | Cohort | Phthalate metabolites | 796 male students who moved to a different university campuses (median age: 20 y) | China | Negative associations between |
| - mEP and sperm concentration | |||||||
| - mEP, MnBP, MCPP, ∑LMWP and sperm motility | |||||||
| - MnOP, MEHP, ∑HMWP and morphologically normal sperm | |||||||
| Positive associations between | |||||||
| - miBP, MEHP and semen volume | |||||||
| - MnOP and progressive motility | |||||||
| - MBzP and sperm with normal morphology | |||||||
| Levels of the phthalate metabolites, except MEHP, decreased, while semen volume and morphologically normal sperm increased after relocation. | |||||||
| Joensen 2012 | (188) | Urinary phthalate metabolites | Cross-sectional | 14 phthalate metabolites | 881 men | Denmark | Men with the highest quartile of %MiNP had higher semen volume and % progressive motility vs lowest quartile |
| Median age 19.1 y | |||||||
| Jurewicz 2013 | (189) | Urinary phthalate metabolites | Cross-sectional | mono(2-ethyl-5OH-MEHP), MEHP, DEP, MEP, BBzP, MBzP, DINP, MINP, DBP, MBP | 269 men attending infertility clinic (sperm concentration ≥ 15 M/mL) | Poland | 5OHMEHP, MEHP and MINP: Negative association with sperm motility |
| Men’s serum FSH, TT and E2 | |||||||
| Kranvogl 2014 | (167) | Urinary phthalates | 9 urinary phthalate monoesters | 136 male partners of infertile couples (mean age, 36.2 y) | Slovenia | MEHP, DMP, DBP, DEHP, MEOHP and sum DEHP levels were negatively associated with sperm concentrations. | |
| MEHP, DBP, MEOHP, sum DEHP levels were negatively associated with sperm motility. | |||||||
| Han 2014 | (190) | Urinary phthalate metabolites | Cross-sectional | Urinary levels of MBP | 232 men from 1 reproductive center | China | Weak association between urinary MBP levels and sperm concentration; men with MBP levels above median were 1.97 times more likely to have sperm concentration below the reference value. |
| MEP | Mean age, 32 y | ||||||
| MEHP | |||||||
| MBzP | |||||||
| PA | |||||||
| Total PA | |||||||
| Semen analysis | |||||||
| Pant 2008 | (191) | Seminal phthalate metabolites | Cross-sectional | Seminal levels of DEP, DEHP, DBP, DMP and DOP | 300 healthy men, aged 21-40 y | India | Negative association between DEP, DBP, DEHP levels and sperm concentration |
| Negative association between DBP, DEHP and sperm motility | |||||||
| Positive association between DEHP level and % abnormal sperm morphology | |||||||
| Pant 2011 | (192) | Seminal fluid | Cross-sectional | DEHP and DBP | 180 healthy men, aged 21-40 y | India | Negative association between DBP, DEHP levels and sperm motility |
| Pant 2014 | (193) | Seminal fluid | Cross-sectional | DEHP | 60 male partners of couples attending the andrology laboratory | India | Negative associations between DEHP and sperm motility, sperm concentration and normal morphology |
| DBP | Age 21-40 y | ||||||
| DEP | |||||||
| Liu 2012 | (194) | Urine | Cross-sectional | 6 urinary phthalate metabolites | 97 men attended fertility clinic | China | NS |
| (MMP, MEP, MBP, MBzP, MEHP and MEOHP) | (median age, 31.5 y) | ||||||
| Pan 2015 | (195) | Urine | Cross-sectional | 14 phthalate metabolites | 1066 men | China | Negative association between MBP, MiBP and % morphologically normal sperm |
| (median age, 29 y) | Negative association between %MEHP and %progressive sperm motility | ||||||
| Smarr 2018 | (196) | Seminal fluid | Cross-sectional | phthalate metabolites | 339 male partners of couples discontinuing contraception to become pregnant, mean age 31.8 years | USA | Negative associations between mEP, mBP, miBP, mBzP and semen volume |
| Thurston 2016 | (197) | Urine | Cross-sectional study | 9 phthalate metabolites | 420 partners of pregnant women Mean age, 32 y | USA | No association between DEHP, DBP, DEP, DOP levels and semen quality. |
| Negative association between MBzP level and sperm motility | |||||||
| Wang 2016 | (198) | Seminal fluid | Cross-sectional | 8 phthalate metabolites | Male partners of subfertile couples | China | Negative associations between MBP, MEHP, MEHHP, MEOHP and semen volume |
| Semen samples (n = 687) Blood samples (n = 342) | Positive associations between MBzP and abnormal sperm heads and tails. | ||||||
| Specht 2014 | (199) | Urinary Secondary oxidized metabolites of DEHP and DiNP | Cross-sectional | 5OH-MEHP oxo-MEHP 5cx-MEPP 7OH-MMeOP |
589 male partners of pregnant women | Greenland Poland Ukraine |
Negative associations between semen volume and proxy-MEHP, 5OH-MEHP and 7OH-MMeOP |
| 7oxo-MMeOP 7cx-MMeOP |
Negative associations between TSC and proxy-MEHP and 5OH-MEHP | ||||||
| Pesticides: Organophosphates | |||||||
| Miranda-Cantreras 2013 | (200) | Erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase activity | Cross-sectional | Erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase activity | 35 healthy farm male workers (unexpected group) and 64 male agricultural workers (exposed group) | Venezuela | No association between erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase and semen quality |
| Melgarejo 2015 | (201) | Urinary levels of 6 DAP metabolites | Cross-sectional | 6 urinary DAP metabolites (organophosphate metabolites) | 116 men, 25-38 years old | Spain | Negative correlation between urinary DMP levels and % sperm motility and morphologically normal sperm |
| (median age, 35.1 y) | Negative association between urinary levels of DMP, DMTP, DMDTP, DAPs and sperm concentration and TSC | ||||||
| Perry 2011 | (202) | Urine | Case control | 6 DAPs | 94 cases and 95 controls | China | Cases had higher urinary DMP levels vs controls |
| Cases had higher sperm concentration and motility | |||||||
| Mean age, 26 y | |||||||
| Pesticides: Pyrethroids | |||||||
| Meeker 2008 | (203) | Urine | Cross-sectional | Pyrethroid metabolites: 3-PBA | 207 men | USA | Men in the highest 3-PBA quartile had lower sperm concentration than men with 3PBA of less than median. |
| CDCCA | Mean age, 36 y | ||||||
| TDCCA | |||||||
| Ji 2011 | (204) | Urine | Cross-sectional | 3-PBA | 240 men from infertility clinic | China | Negative association between 3-PBA level and sperm concentration |
| Imai 2014 | (205) | Urine | Cross-sectional | 3-PBA | 323 university students | Japan | NS |
| Radwan 2014 | (206) | Urine | Cross-sectional | Pyrethroid metabolites: 3-PBA | 334 men attended infertility clinic | Poland | Positive association between pyrethroid metabolite levels and %sperm with abnormal morphology |
| CDCCA | Mean age: 32.2 y | Negative association between DBCA and curvilinear velocity and linearity | |||||
| TDCCA | |||||||
| DBCA | |||||||
| Xia 2008 | (207) | Urine | Cross-sectional | 3-PBA | 376 men with nonobstructive infertility | China | Men who had urinary creatinine-adjusted 3-PBA level in the 4th quartile had higher risk of having sperm concentration < 20 million/mL |
| Mean age 30.4 y | |||||||
| Pesticides: Organochlorines | |||||||
| Abdelouahab 2011 | (208) | Serum | Cross-sectional | p-p′ DDE | 52 men from a fertility clinic. age 25 – 50y | Canada | NS |
| Abou Ghayda 2020 | (209) | Serum at the age of 8-9 y | Cohort study | HCB | 152 young men provided semen samples | Russia | Negative association between semen volume and HCB and βHCH |
| HCH | |||||||
| p,p’-DDE | |||||||
| Aneck-Hahn 2007 | (210) | Plasma | Cross-sectional | p,p’-DDE | 311 men residing in the endemic malaria area | South Africa | Negative association between p,p’-DDE level and semen volume and mean CASA motility |
| Mean age 23 y | |||||||
| Ayotte 2001 | (211) | Serum | Cross-sectional | p,p’-DDE | 24 young men | Mexico | Negative association between serum p,p’-DDE level and semen volume and TSC |
| Mean age 21 y | |||||||
| De Jager 2006 | (212) | Plasma | Cross-sectional | p,p’-DDE | 116 men residing in the area of DDT use | Mexico | Negative association between plasma p,p’-DDE and percentage of sperm motility |
| Mean age 27 y | |||||||
| Hauser 2003 | (213) | Serum | Cross-sectional | p, p’-DDE | 212 male partners of subfertile couples | USA | NS |
| Mean age 36 y | |||||||
| Mumford 2015 | (214) | Serum | Cross-sectional | 9 organochlorine pesticides | 501 male partners of couples trying to conceive | USA | Highest quartiles of some pesticides were associated with higher sperm concentration, total sperm count and sperm motility when compared to the lowest quartile. |
| Mean age = 31.8 y | |||||||
| Pant 2014 | (215) | Seminal plasma | Cross-sectional | P,p’-DDE | 193 infertile men | India | Men in the highest quartile of lindane or p,p-DDE had lower sperm concentration and motility. |
| lindane | 85 fertile men | ||||||
| Mean age, 28 y | |||||||
| Specht 2015 | (216) | Serum | Cross-sectional | HCB | 589 fertile men | Greenland | Negative association between HCB and semen volume (only men in Greenland) |
| Median age: | Poland | ||||||
| Greenland, 30.6 y | Ukraine | ||||||
| Poland, 29.6 y | |||||||
| Ukraine, 25 y | |||||||
| Perfluorinated Compounds (PFCs) | |||||||
| Louis 2015 | (217) | Serum | Cross-sectional | 7 PFCs | 501 male partners of couples planning pregnancy | USA | Positive association between PFNA level and % morphologically normal sperm by Strict criteria |
| Mean age ± SD, 31.8 ± 4.9 y | (NS by WHO criteria) | ||||||
| NS (semen volume, sperm concentration, TSC, %motility) | |||||||
| Joensen 2009 | (218) | Serum | Cross-sectional | 10 PFAAs | 105 men from general population | Denmark | Men with high levels of combined PFOS and PFOA had lower number of morphologically normal sperm than men with low levels of PFOS and PFOA. |
| Median age 19 y | |||||||
| Lewis 2015 | (219) | Serum | Cross-sectional | 4 PFASs | 857 men from general population | USA | NS with T |
| Age 12-80 y | |||||||
| Petersen 2018 | (220) | Serum PFASs | Cross-sectional | Serum PCBs, PFASs | 263 men, aged 24-26 y | Faroe island | NS |
| Joensen 2013 | (221) | Serum PFCs | Cross-sectional | 14 PFCs | 247 healthy men from general population | Denmark | PFHpS had negative association with progressive motility |
| Median age = 19 y | |||||||
| Raymer 2012 | (222) | Plasma, seminal fluid | Cross-sectional | PFOS, PFOA | 256 men came for fertility assessment | USA | NS |
| Median age = 41 y | |||||||
| Toft 2012 | (223) | Serum | Cross-sectional | 4 PFCs | 588 partners of pregnant women Median age: |
Greenland Poland Ukraine |
Combined 3 countries: - Men who had PFOS or PFHxS level in the 3rd tertile had lower % morphologically normal sperm than men in the 1st tertile |
| Greenland, 31.3 y | Ukraine | - Men who had PFOA level in the 3rd tertile had higher % sperm motility | |||||
| Poland, 29.6 y | |||||||
| Ukraine, 26.2 y | |||||||
| PCBs and dioxins | |||||||
| Abdelouahab 2011 | (208) | Serum | Cross-sectional | Sum of PCB-153, PCB-180, PCB-138 | 52 men from a fertility clinic. Age 25 – 50y | Canada | NS |
| Dallinga 2002 | (224) | Serum and semen | Cross-sectional | PCB 118, 138, 153, 180, | 65 men from infertility clinic | The Netherlands | Among men with good semen quality: |
| Mean age: | Negative association between serum ∑PCB and TSC and progressive motile sperm | ||||||
| Male factor subfertility group: 34.5 y | |||||||
| Female factor subfertility group: 36.7 y | |||||||
| Hauser 2003 | (213) | Serum | Cross-sectional | 57 PCB congeners | 212 male partners of subfertile couples | USA | Negative association between PCB-138 level and % sperm motility and % morphologically normal sperm |
| Mean age 36 y | |||||||
| Minguez-Alarcon 2017 | (225) | Serum | Cohort (peripubertal exposure) | Serum PCBs dioxins, furans, PCBs, (age 8-9 y) Semen samples (age 18-19 y) | Healthy boys, aged 8–9 y (n=516) and 18–19 y (n=133) | Russia | Serum TCDD and PCDD TEQs: Negative association with sperm concentration, TSC, total motile sperm count |
| Serum PCBs, furans and total TEQs: no association | |||||||
| Mumford 2015 | (214) | Serum | Cross-sectional | 36 PCB congeners | 501 male partners of couples trying to conceive | USA | Highest quartiles of some congeners were associated with higher volume, total sperm count and sperm motility when compared to the lowest quartile |
| Mean age = 31.8 y | |||||||
| Paul 2017 | (226) | Serum | Cross-sectional | DL-PCBs | Men, aged 30–55 y, from subfertile couples | Spain | Men with normal semen quality: negative associations between |
| - low semen quality (n = 24) | - PCB-118 and semen volume | ||||||
| - normal semen quality (n = 26) | - PCB-189 and progressive motility | ||||||
| positive associations: | |||||||
| - PCB-77, -123, total nonortho PCBs | |||||||
| (sperm with normal morphology) | |||||||
| Men with low semen quality: | |||||||
| positive associations between | |||||||
| - PCB-118, mono-ortho PCBs, PDLPCBs and semen volume | |||||||
| - PCB-77, PCB-81 and morphologically normal sperm | |||||||
| Petersen 2015 | (227) | Serum | Cross-sectional | PCB28,105,118,156, 52,101,153,138, 180 | 266 fertile men | Faroe Island | NS |
| Median age, 34.8 y | |||||||
| Petersen 2018 | (220) | Serum | Cross-sectional | PCBs | 263 men, aged 24–26 years | Faroe Island | NS |
| Richthoff 2003 | (228) | Serum | Cross-sectional | PCB 153 | 305 young men from general population, aged 18-21 y | Sweden | Negative association between PCB 153 level and %sperm motility by CASA |
| Rignell-Hydbom 2004 | (229) | Serum | Cross-sectional | PCB-153 | 195 fishermen, aged 24-65 y | Sweden | Lower sperm motility in men with the highest PCB-153 quintile as compared with men in the lowest quintile |
| Rignell-Hydbom 2005 | (230) | Serum | Cross-sectional | PCB-153 | 176 fishermen | Sweden | NS |
| Mean age: 47 y | |||||||
| Rozati 2002 | (231) | Semen | Cross-sectional | PCBs | 21 infertile, mean age 33.7 y | India | Negative association between PCBs and total progressive motility |
| 32 controls, mean age 32.5 y | |||||||
| Spano 2005 | (232) | Serum | Cross-sectional | PCB-153 | 707 men | Greenland | NS |
| Mean age: | Sweden | ||||||
| Inuit men 31.1 y | Ukraine Poland | ||||||
| Swedish fishermen 47.1 y | |||||||
| Warsaw men 30.3 y | |||||||
| Kharkiv men 26.6 y | |||||||
| Toft 2006 | (233) | Serum | Cross-sectional | CB-153 and p,p’-DDE | Men, aged > 18 y from All regions in Greenland (n = 194) | Greenland | Negative association between CB-153 level and sperm motility. |
| Fishermen from Sweden (n = 185) | Sweden | No association between CB-153 and sperm concentration or %morphologically normal sperm | |||||
| Residents of Kharkiv in Ukraine (n= 195) | Ukraine | ||||||
| Residents of Warsaw in Poland (n = 189) | Poland | ||||||
| Vitku 2016 | (179) | Plasma and Seminal plasma | Cross-sectional | 6 PCB congeners (PCB 28, 101, 118, 138, 153, 180) | 191 men attended infertility clinic | Czech | ∑PCBs (PCB 180, -153, -118 and -138) had positive association with sperm concentration and TSC |
| Mean age 35 y | |||||||
| Flame retardants | |||||||
| Albert 2018 | (184) | Hair | Cross-sectional | 8 PBDE congeners | 153 healthy men, aged 18-41 y | Canada | NS (tendency to negative association with sperm concentration and sperm motility) |
| Yu 2018 | (234) | Seminal fluid | Cross-sectional | PBDEs | Cases: men aged 20–50 y residing at an e-waste dismantling workshop (n=32) | China | TSC, progressive motility, and total motile sperm were lower in cases than in controls. |
| Controls: men aged 24–46 y (n=25) | Negative associations between seminal BDE-47 and sperm concentration and TSC | ||||||
| Abdelouahab 2011 | (208) | Serum | Cross-sectional | BDE-47, BDE-99, BDE-100, BDE-153 | 52 men from a fertility clinic. Age 25 – 50y | Canada | Negative association with sperm motility |
| Akutsu 2008 | (235) | Serum | Cross-sectional | 29 PBDE congeners | 10 men, aged 18 – 21 y | Japan | HxBDE-153 showed significant negative association with sperm concentration |
| Mumford 2015 | (214) | Serum | Cross-sectional | 10 PBDE congeners and PBB-153 | 501 male partners of couples trying to conceive | USA | Highest quartiles of some congeners were associated with lower sperm motility and higher sperm concentration and % of abnormal morphology when compared to the lowest quartile |
| Mean age = 31.8 y | |||||||
| Toft 2014 | (236) | Serum | Cross-sectional | BDE-28, 47, 99,100, 153, 154 and 183, and BB-153 | 299 partners of pregnant women | Greenland, Poland and Ukraine | BDE-47 and BDE 153: NS (no consistent associations across countries) |
| Median age: | |||||||
| Greenland, 32.1 y | |||||||
| Poland, 29.6 y | |||||||
| Ukraine, 26.1 y |
Only statistically significant findings have been shown.
Only studies reporting standard semen quality parameters are included.
NS, no statistically significant association.