Infertile men more likely to have impaired kidney function, study says

In a recent study published in the journal Scientific Reports, researchers investigated the association between male infertility and renal function. They used a large cohort comprising 11,602 participants (5,494 childless men and 6,108 fathers). They found that childless men were likelier to have a low estimated glomerular filtration rate (< 60 ml/min/1.73m2) and dipstick proteinuria independent of age, socioeconomic status, or traditional renal risk factors such as hypertension, diabetes, and metabolic function.

These findings contribute novel evidence to a growing body of literature highlighting the role of male fertility in altering the risk or pathology of several non-communicable chronic diseases. Study outcomes suggest that men with reduced fertility may represent a population in need of routine kidney function evaluation.

Study: Prevalence of impaired renal function among childless men as compared to fathers: a population-based study. Image Credit: BigBlueStudio / Shutterstock

The non-reproductive impacts of male infertility

Infertility has long been down upon in cultures across the world, with many traditions considering a person’s inability to reproduce an ill omen, curse, or divine punishment. Recent research suggests that while male infertility-associated ill omens are yet to be discovered, the dangers of the condition may extend far beyond just reproduction or the reproductive system. Previous studies have identified infertile men at heightened risk of ischemic disease and diabetes.

Male childlessness, a commonly invoked proxy for the much-harder-to-elucidate male infertility, has been associated with cardiovascular risk factors, including hyperlipidemia, hyperglycemia, and hypertension, with these individuals being much more likely than fertile men to consume prescription metabolic syndrome and hypertension medication. Unfortunately, research extending these investigations into renal evaluations remains lacking. The current study aims to add to the work of Eisenberg et al., hitherto the sole publication exploring the association between male infertility and renal disease.

About the study

The present study aims to evaluate if male childlessness (herein a proxy for male in- or subfertility) is associated with impaired renal function (eGFR < 60 mL/min/1.73 m2) or dipstick proteinuria. The study sample cohort was derived from the Malmö Preventive Project (MPP), a long-term, longitudinal, population-based sample group established in the 1970s, with detailed information on creatinine levels and urine dipstick results essential from the measurement of glomerular filtration rate (eGFR) and dipstick test for protein in the urine. MPP also records and maintains participants’ fatherhood status, further meeting the current study’s requirements.

MMP data revealed 22,444 men between the ages of 25 and 63 enrolled between 1974 and 1994. Data collection included socioeconomic, demographic, lifestyle, and medical history records obtained from participants via a generalized questionnaire. Experimental assays and characterizations were carried out using participant-submitted urine samples and author-recorded physical examinations. The Swedish Tax Agency Statistics (STAS) provided data on the number of children per participant at baseline, with each record being associated with a unique personal identification number.

Jaffe’s alkaline picrate assay and the CKD-EPI creatinine formula (2021) were used to quantify the concentrations of serum creatine and eGFR, respectively. Proteinuria was investigated using a semi-quantitative urine dipstick test. Finally, two logistic regression models were used to elucidate any statistical associations (expressed as crude odds ratios [ORs]) between male childlessness and eGFR and/or dipstick proteinuria. The first model took into consideration men’s marital, socioeconomic, and occupational status, while the second adjusted for previously reported renal risk factors such as age, marital status, smoking status, and CKD-associated comorbidities.

Study findings and conclusions

“In this population-based study we found that childless men, as compared to fathers, are more prone to show signs of renal disease as decreased eGFR and dipstick proteinuria. The likelihood of dipstick proteinuria, with or without concomitant decrease in eGFR, remained statistically significant even after adjustment for comorbidities and traits known to be linked to impaired renal function.”

Of the 22,444 participants initially scouted from the MPP cohort, the exclusion of individuals with incomplete data and those above the age of 45 years resulted in a final cohort size of 11,602 individuals – 47.3% (n = 5494) were childless. eGFR evaluations revealed that childless men (3.1%) were more likely to present with an eGFR < 60 mL/min/1.73 m2 than their fertile counterparts (2.3%). These findings were consistent with those found during dipstick proteinuria evaluations (7.1% in childless men and 4.9% in fathers). Surprisingly, these associations remained significant in all but one, including the logistic regression model.

These findings highlight the heightened renal disease risk of childless (in- or sub-fertile) men when compared to Fathers, suggesting that the former is a target population from frequent renal monitoring, potentially presenting a novel tool in the clinicians’ future arsenal against renal diseases.