Increased trends in reported sexually transmitted infections according to age groups and sex in Spain, 2016-2022.

Objective: Our objective was to assess trends in three sexually transmitted infections (STIs) - gonorrhoea, chlamydia and syphilis - in Spain, by age group and sex from 2016 to 2022.

Study design: Retrospective observational study.

Methods: Data from epidemiological surveillance system were used to calculate the incidence rate for each STIs by age group and sex. Poisson regression was employed to examine the trends for 2016 to 2022.

Results: For gonorrhoea, higher incidence rates were observed among men than women for all period. The incidence rate ratio (IRR) varied between 1.14 (95% CI 1.12-1.16) for the 15-19 age group to 1.24 (1.23-1.25) for the 35-44 age group among men, and between 1.14 (1.09-1.19) for 55 years or more to 1.27 (1.24-1.29) for the 15-19 age group among women. For chlamydia, women showed higher incidence rate for all age groups than men during the period. Individuals aged 55 years and over showed the highest increase, IRR = 1.30 (1.27-1.34) for men, while it was the lowest for women, IRR = 1.22 (1.16-1.27). The incidence rates for syphilis were lower than for the other STIs. IRR values varied between 1.04 (1.02-1.06) in the 20-24 age group and 1.15 (1.14-1.16) in the 35-44 age group for males; and between 1.13 (1.06-1.16) for the 25-34 age group and 1.18 (1.13-1.25) for the 25-34 age group for females.

Conclusion: STIs are more frequent in people aged 25-34 and are increasing in all age groups. However, the rise is most pronounced among older men and among younger women.