P–110 Does the Body Mass Index affect sperm quality?
Authors: Badalotti-Teloken I , Teloken C , Dornelles V , Arent A , Petracco A , Badalotti M 
Published: August 2021

Study question

Does the body mass index (BMI) have an impact on semen analysis results?

Summary answer

The increase in BMI has a negative impact on sperm motility.

What is known already

Obesity is an increasingly prevalent health condition worldwide and can affect male fertility in various ways. It is known that obesity can cause testicular inflammation, higher testicular temperature, hypogonadism, sperm DNA fragmentation, and erectile dysfunction. However, there are still conflicting data regarding the correlation between BMI and semen parameters in the seminal analysis.

Study design, size, duration

Observational, cross-sectional, retrospective study using data from 1147 patients seen at a private infertility clinic between 2010 and 2020. The data were collected from electronic records in a prospective database.

Participants/materials, setting, methods

Patients were divided according to BMI (healthy weight, overweight, obesity classes I, II, III), and their seminal profiles were compared, according to 2010’s World Health Organization’s parameters. Cancer, cryptorchidism, viral orchitis, altered karyotype, Y chromosome microdeletions, vasectomy reversion, and testosterone use were excluding factors. Student t-tests and multiple linear regression were used for statistical analysis. The results were adjusted for age, alcohol, tobacco, and drug use, medication intake, physical activity, comorbidities, and scrotum heat factors.

Main results and the role of chance

From a total of 1384 patients, 219 were excluded. The BMI varied between 18,9 and 50,8 kg/m². From the 1147 patients, 297 had BMI 18.5–24.9 kg/m² (healthy weight, group 1), 611 had BMI 25–29.9 kg/m² (overweight, group 2), 179 had BMI 30–34.5 kg/m² (obese, group 3), 60 had BMI ≥ 35 kg/m² (extremely obese, group 4). The mean age for groups 1 through 4 was 37.6, 38.5, 38.2, and 36.5 years old. The comparison of the groups’ seminal parameters shows a significant decrease in progressive and total motility in patients with BMI ≥ 35 kg/m².The progressive motility was 43.8% in group 1, 44.1% in group 2, 42.4% in group 3, and 35.2% in group 4 (p = 0.07) and the total motility was 54.4%, 54.1%, 53.6%, and 45.9%, respectively (p = 0.012). The complementary analysis determined BMI 29 kg/m² as the cutoff for negative impact on progressive motility (p = 0.044) and 31 kg/m² on total motility (p = 0.036). The results were still significant after age, use of cannabis, and hypertension adjustments – the other possible interfering factors were not significant.

Limitations, reasons for caution

Besides the fact that this was a retrospective study, it also has a smaller sample size of patients with extreme obesity. This is probably related to the fact that the patients seeking reproductive treatment in a private clinic have a greater purchasing power and lower prevalence of obesity.

Wider implications of the findings: In this study, sperm quality is negatively affected by BMI, with impairment since 29 kg/m² for progressive and 31 kg/m² for total motility. Our data support the potential deleterious role of obesity on semen parameters, reinforcing the importance of weight control in infertility prevention.

Trial registration number

Not applicable