Higher BMI Increases Risk of Severe COVID-19, Respiratory Infections

Bastian Bohrmann, MSc

Credit: University of Oxford

A new study found high body mass index (BMI) is associated with an increased risk of hospitalization or death due to severe infectious respiratory diseases, including COVID-19, lower respiratory tract infections (LRTIs), and upper respiratory tract infections (URTIs).¹

Bastian Bohrmann, MSc, Nuffield Department of Population Health, University of Oxford, and investigators found 20,302 participants were hospitalized for or died of severe infectious respiratory disease during the mean follow-up period of 11.8 years.

Among these cases, 1296 were for COVID-19, 17,085 were for LRTIs, and 1504 were for URTIs. Of the COVID-19 cases, 144 participants died without prior hospitalization.

The Analysis

Data for the analysis were collected from the UK Biobank, including a prospective cohort of more than 5 million individuals recruited from the general population. Baseline assessments were performed between 2006-2010 and the follow-up was completed in 2021.

Patients with prevalent chronic respiratory diseases, previous hospitalization for infectious respiratory diseases, and missing or extreme values for key variables were excluded.

Investigators used Cox proportional hazards models to calculate hazard ratios (HRs) for the association between BMI categories and the risk of hospitalization or death due to COVID-19, LRTIs, or URTIs. The analyses were adjusted for age, sex, region, race, deprivation score, education, smoking, and alcohol intake.

After exclusions, 476,176 participants remained and the data exhibited For COVID-19, the incidence rates ranged from 1.2 (95% CI, 1.1-1.3) per 1000 person-years for participants with a BMI less than 25 to 5.8 (95% CI, 4.7-7.1) per 1000 person-years for participants with a BMI in the range of 35 to 60.

The incidence rates for LRTIs ranged from 25.6 (95% CI, 25.0-26.2) per 1000 person-years to 55.5 (95% CI, 53.9-57.2) per 1000 person-years, while for URTIs, a range of 2.2 (95% CI, 2.0-2.4) per 1000 person-years to 4.4 (95% CI, 4.1-4.7) per 1000 person-years was observed.

Investigators calculated different BMI categories with the adjusted HRs for severe infectious respiratory disease, including COVID-19, LRTIs, and URTIs.

When evaluating for COVID-19, it ranged from 0.62 (95% CI, 0.54-0.71) for BMI less than 25 to 2.38 (95% CI, 2.07-2.74) for BMI in the range of 35 to 60.

For LRTIs, the range spanned from 1.02 (95% CI, 0.99-1.05) to 1.91 (95% CI, 1.83-2.00), while URTIs ranged from 0.79 (95% CI, 0.72-0.88) to 1.40 (95% CI, 1.20-1.64).

Higher BMI Indicates Higher Risk of Severe Infection

The investigators stated these findings suggest higher BMI is associated with an increased risk of severe infectious respiratory disease, including COVID-19, LRTIs, and URTIs.

The increased risk was particularly pronounced for COVID-19, with participants in the highest BMI category exhibiting more than twice the risk when compared with those in the lowest BMI category, indicating the importance of maintaining a healthy weight to reduce the risk of severe infectious respiratory disease.

“This study found log-linear associations between higher BMI and increased risk of hospitalizations for or death due to severe COVID-19 and URTIs throughout the BMI categories examined, and with LRTIs for BMI greater than 25,” investigators wrote.

References:

1. Bohrmann B, Massa MS, Ross S, Lewington S, Lacey B. Body Mass Index and Risk of Hospitalization or Death Due to Lower or Upper Respiratory Tract Infection. JAMA. 2023;329(17):1512–1514. doi:10.1001/jama.2023.2619