title: Choice of underwear and male fecundity in a preconception cohort of couples.
abstract: Our objective was to investigate the relationship between male underwear-type worn during daytime/bedtime and male fecundity as measured by semen quality and time-to-pregnancy. We used data from a prospective preconception cohort conducted in 16 counties in Michigan and Texas, USA. 501 couples were enrolled and followed for 12 months of trying, which facilitated capture of time-to-pregnancy (in cycles), 6-cycle conception delay, and 12-month infertility. Male partners provided semen samples via in-home collection for next-day semen analysis comprised of 35 semen quality endpoints. At enrollment, men provided information on type of underwear worn during daytime and bedtime and were classified into 6 categories by underwear choice (n = 491): (i) briefs day/night, (ii) boxer-briefs day/night, (iii) boxers day/night, (iv) briefs day and boxers/none at night, (v) boxer-briefs day and boxers/none at night, (vi) boxers day and none at night. 473 (96%) men had semen analysis performed. Men switching from their usual daytime underwear to boxers/none for bed (groups 4, 5, 6) had the most evidence of change in semen quality endpoints (10 of 11 differences) relative to men wearing briefs day/night (group 1). Group 4 men had lower percent of sperm with coiled tail (β = -0.18, 95% CI: -0.35, -0.01), higher percent round (β = 0.22, 95% CI: 0.01, 0.42), number of immature sperm (β = 0.44, 95% CI: 0.11, 0.77), and amplitude head displacement (β = 0.57, 95% CI: 0.10, 1.03). Group 5 men had higher sperm head perimeter (β=0.17, 95% CI: 0.002, 0.34), amplitude head displacement (β = 0.47, 95% CI: 0.03, 0.91), percent cytoplasmic droplet (β = 0.44, 95% CI: 0.11, 0.77) and high DNA stainability (β=0.39, 95% CI: 0.01, 0.78). After false discovery rate control, no differences remained significant. No significant differences in time-to-pregnancy, conception delay, or infertility were observed. In summary, male underwear choice is associated with few differences in semen parameters; no association with time-to-pregnancy is observed providing reassurance to couples attempting pregnancy.
authors.affiliation: Office of the Director, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health & Human Development, Rockville, MD, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Sapra
authors.affiliation: Department of Urology and Obstetrics and Gynecology, Stanford University, Stanford, CA, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Eisenberg
authors.affiliation: Biostatistics and Bioinformatics Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health & Human Development, Rockville, MD, USA.
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.affiliation: Biostatistics and Bioinformatics Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health & Human Development, Rockville, MD, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Office of the Director, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health & Human Development, Rockville, MD, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Buck Louis
mesh_terms: D048430:Cell Shape; D002755:Choice Behavior; D003020:Clothing; D005191:Family Characteristics; D005260:Female; D005298:Fertility / Q000502:physiology*; D006801:Humans; D007248:Infertility, Male; D008297:Male; D011247:Pregnancy; D011446:Prospective Studies; D055101:Semen Analysis; D013076:Sperm Count; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology*; D061685:Time-to-Pregnancy
keywords: infertility; lifestyle; semen quality; time-to-pregnancy; underwear