Swimming-induced pulmonary oedema more likely to occur in women, older people

Among competitive and recreational swimmers, women and older people are at higher risk of having swimming-induced pulmonary oedema (SIPE), according to a study from Sweden.

The study estimated 4-year incidence of SIPE in a mixed group of competitive and recreational swimmers during Sweden’s largest open-water swimming event, Vansbrosimningen. SIPE diagnosis was based on clinical findings, while pulmonary oedema was evaluated by lung ultrasound. Researchers collected data on patient characteristics, clinical findings, and race.

Based on 47,573 consecutive swimming distances, 322 swimmers presented with acute respiratory symptoms (0.68 percent) and were treated at the mobile medical unit. Of these, 211 patients (0.44 percent) received a SIPE diagnosis.

The resulting annual incidence of SIPE was 0.34 percent at year 1, 0.47 percent at year 2, 0.41 percent at year 3, and 0.57 percent at year 4. Most patients diagnosed with SIPE were women (90 percent), despite about equal percentages of men and women participating in the swimming event (47 percent men and 53 percent women). Overall, SIPE had an incidence of 0.75 percent in women and 0.09 percent in men.

Of note, the incidence increased with age, jumping from 0.08 percent in the youngest age group (18–30 years) to 1.1 percent in the oldest age group (≥61 years).

Multiple logistic regression analysis revealed that the odds of developing SIPE were 8.59 times higher for women than men and 12.74 times higher for the oldest than the youngest age group.