TY - JOUR

T1 - Infertility in a Cohort of Male Danish Firefighters

T2 - A Register-Based Study

AU - Petersen, Kajsa U.

AU - Hansen, Johnni

AU - Ebbehøj, Niels E.

AU - Bonde, Jens P.

PY - 2019

Y1 - 2019

N2 - Our aim in this study was to examine infertility among male firefighters in Denmark. Thus, we established a cohort of 4,710 past and present male Danish firefighters through personnel and membership records obtained from employers and trade unions. Information on vital status and infertility from the Danish Civil Registration System, the In Vitro Fertilisation Register, and the National Patient Register for the period 1984-2017 was linked to cohort members using their Danish personal identification numbers. Hazard ratios and corresponding 95% confidence intervals were estimated for male-factor infertility and overall infertility through Cox regression analyses comparing the firefighters with 2 reference groups: a sample of employees and military men. Among the full-time firefighters, the risk of male-factor infertility was increased in comparison with the sample of employees (In Vitro Fertilisation Register model: hazard ratio = 1.46 (95% confidence interval: 1.10, 1.94); National Patient Register model: hazard ratio = 1.53 (95% confidence interval: 1.18, 1.98)). Results were less consistent using the military men as the reference group. Further, the increase in infertility seemed restricted to duration of time employed as a firefighter. No increase in risk of either male-factor infertility or overall infertility was seen among the part-time/volunteer firefighters. Thus, full-time firefighting was associated with a greater risk of being diagnosed with male-factor infertility in our cohort.

AB - Our aim in this study was to examine infertility among male firefighters in Denmark. Thus, we established a cohort of 4,710 past and present male Danish firefighters through personnel and membership records obtained from employers and trade unions. Information on vital status and infertility from the Danish Civil Registration System, the In Vitro Fertilisation Register, and the National Patient Register for the period 1984-2017 was linked to cohort members using their Danish personal identification numbers. Hazard ratios and corresponding 95% confidence intervals were estimated for male-factor infertility and overall infertility through Cox regression analyses comparing the firefighters with 2 reference groups: a sample of employees and military men. Among the full-time firefighters, the risk of male-factor infertility was increased in comparison with the sample of employees (In Vitro Fertilisation Register model: hazard ratio = 1.46 (95% confidence interval: 1.10, 1.94); National Patient Register model: hazard ratio = 1.53 (95% confidence interval: 1.18, 1.98)). Results were less consistent using the military men as the reference group. Further, the increase in infertility seemed restricted to duration of time employed as a firefighter. No increase in risk of either male-factor infertility or overall infertility was seen among the part-time/volunteer firefighters. Thus, full-time firefighting was associated with a greater risk of being diagnosed with male-factor infertility in our cohort.

U2 - 10.1093/aje/kwy235

DO - 10.1093/aje/kwy235

M3 - Journal article

C2 - 30452532

VL - 188

SP - 339

EP - 346

JO - American Journal of Epidemiology

JF - American Journal of Epidemiology

SN - 0002-9262

IS - 2

ER -