Severe Obesity Linked to Higher Asthma Odds in Study of More Than 600,000 Israeli Teenagers

Key Takeaways

• A study involving 603,552 Israeli adolescents found that higher body weight categories were associated with greater odds of asthma.
• Among Arab Israeli adolescents with class 3 obesity, the adjusted odds of asthma were 52% higher than among those with normal weight.
• The association between obesity and asthma was broadly similar among Arab Israeli and Jewish Israeli teenagers, although their asthma medication patterns differed.
• Earlier research supports a two-way relationship: obesity is associated with subsequent asthma diagnoses, while children with asthma may also be more likely to develop obesity.
• The Israeli study was cross-sectional, meaning it cannot establish whether obesity causes asthma or whether asthma contributes to weight gain.

Introduction

A study of 603,552 Israeli adolescents found that severe obesity was associated with higher odds of asthma.

Teenagers with severe obesity may have greater odds of asthma, according to a large Israeli study that also identified differences in how respiratory medications are used across population groups.

Published October 12, 2026, in Respiratory Medicine, the research examined health records from 603,552 adolescents aged 14 to 19. Higher weight categories were consistently associated with greater odds of asthma, with some of the strongest associations observed among teenagers with severe obesity.

The findings are consistent with earlier research connecting childhood obesity to respiratory problems. However, the Israeli study adds a different perspective by comparing Arab Israeli and Jewish Israeli adolescents within the same national health insurance system.

Although the relationship between body weight and asthma was similar in both groups, researchers found differences in the use of inhaled and systemic corticosteroids, raising additional questions about asthma management.

What the Study Examined

Researchers from Ben-Gurion University of the Negev, Clalit Health Services, and Meir Medical Center analyzed electronic medical records collected between January 2007 and December 2022.

The study included 313,936 Arab Israeli adolescents and 289,616 Jewish Israeli adolescents. The Jewish Israeli comparison group was selected to have a socioeconomic distribution similar to that of the Arab Israeli group.

Participants were divided into six weight categories: underweight, normal weight, overweight, obesity, class 2 obesity, and class 3 obesity.

The researchers examined recorded asthma diagnoses and asthma accompanied by purchases of inhaled corticosteroids, inhaled bronchodilators, or systemic corticosteroids. Medication use was defined as at least three purchases during the observation period.

They also examined asthma-related emergency department visits, hospitalizations, and selected markers of allergic inflammation.

The statistical analyses accounted for sex, socioeconomic status, geographic district, and birth cohort.

For each participant, the researchers used the highest recorded body mass index (BMI) during the study period. This approach was intended to capture whether an adolescent had experienced obesity at any point during the observation period.

Unlike a clinical trial, the study did not assign participants to different weight categories or treatments. It examined existing health records to identify associations between weight status and asthma (Treister-Goltzman et al., 2026).

What Researchers Found

Higher Weight Categories Were Associated With More Asthma

Among Arab Israeli adolescents, asthma was recorded in 8.9% of those with normal weight, compared with 14.7% of those with class 3 obesity. This represents a difference of 5.8 percentage points between the two groups.

After adjustment for demographic factors, higher weight categories were associated with greater odds of asthma.

Adolescents classified as overweight had 16% higher adjusted odds of asthma than those with normal weight. Among those with class 3 obesity, the adjusted odds were 52% higher (adjusted odds ratio [aOR], 1.52; 95% confidence interval [CI], 1.35–1.70).

Researchers observed similar patterns among Jewish Israeli adolescents, although the precise estimates differed between the groups.

Importantly, the adjusted odds ratio describes a statistical association after accounting for selected demographic factors. It does not mean asthma prevalence increased by 52 percentage points.

Because the study was cross-sectional, the findings cannot establish that obesity caused asthma.

Severe Obesity Was Also Associated With Asthma Medication Use

Among Arab Israeli adolescents with class 3 obesity, researchers reported higher adjusted odds of asthma accompanied by several types of medication use:

All comparisons used adolescents with normal weight as the reference group.

These results show that adolescents with class 3 obesity had higher adjusted odds of having asthma recorded alongside purchases of specific respiratory medications. They do not establish that obesity caused more severe asthma or directly increased the need for treatment.

Systemic corticosteroids are often prescribed during significant asthma exacerbations, but medication purchases alone cannot reliably establish disease severity. Differences in prescribing practices, access to care, and whether patients follow their treatment plans may also influence these findings.

Additional analyses found that higher weight categories were associated with greater asthma-related emergency department and hospital use in both ethnic groups.

Asthma Medication Patterns Differed Between Population Groups

Although the association between obesity and asthma was similar among Arab Israeli and Jewish Israeli adolescents, medication use differed.

Jewish Israeli adolescents generally had greater use of inhaled corticosteroids, while Arab Israeli adolescents had greater use of systemic corticosteroids.

Inhaled corticosteroids are an important component of long-term asthma management because they reduce airway inflammation and help prevent exacerbations.

Systemic corticosteroids may be necessary during severe attacks, but repeated courses can expose patients to additional adverse effects.

The researchers could not determine why the treatment patterns differed. Possible explanations include differences in prescribing practices, treatment adherence, disease characteristics, or health care utilization.

Importantly, shared national insurance coverage does not necessarily mean that patients receive identical care.

How the Findings Compare With Earlier Research

A US Study of More Than 623,000 Children Found a Similar Pattern

The Israeli findings are consistent with an earlier American study involving 623,358 children and adolescents enrolled in Kaiser Permanente Southern California.

In that longitudinal analysis, Black et al. (2013) examined whether childhood weight categories were associated with subsequently diagnosed asthma.

The researchers found that asthma incidence increased from 16.9 cases per 1,000 person-years among children with normal weight to 22.3 cases per 1,000 person-years among those with extreme obesity.

After adjustment, children with extreme obesity had a 37% higher relative risk of developing asthma than children with normal weight.

The American study is particularly relevant because it followed participants over time, allowing researchers to examine asthma diagnoses occurring after the recorded weight classification.

However, it remained observational and could not prove that obesity caused asthma.

Together, the American and Israeli studies provide evidence that the relationship between excess weight and asthma is observable across different health care systems and populations.

A Meta-Analysis Found Evidence of a Two-Way Relationship

A systematic review and meta-analysis by Shan et al. (2020) examined nine cohort studies investigating the relationship between childhood obesity and asthma.

The pooled analysis found that children and adolescents with obesity had a 39% higher relative risk of developing physician-diagnosed asthma compared with those without obesity.

However, the researchers also found evidence of the reverse relationship.

Children with asthma had a 47% higher relative risk of subsequently developing obesity.

This is important because it complicates the assumption that obesity necessarily develops first and contributes to asthma.

Children with asthma may experience activity limitations, sleep disturbances, or other circumstances that influence weight. Obesity and asthma may also share biological or environmental influences.

The meta-analysis found substantial differences between studies examining obesity and subsequent asthma, meaning its pooled estimate should not be treated as a universal risk figure.

Another Study Found That Asthma May Precede Obesity

Further evidence comes from a prospective study by Chen et al. (2017), which followed 2,171 initially nonobese children aged 5 to 8 in Southern California.

Children who had asthma at the beginning of the study had a 51% higher adjusted hazard of developing obesity during follow-up than children without asthma.

The researchers observed a similar association in an independent group of 2,684 children.

This study is especially useful for interpreting the Israeli findings because it examined the opposite sequence: asthma preceding obesity.

Taken together, these studies indicate that obesity and asthma may influence one another through several pathways, although the available observational evidence cannot fully establish the underlying causal relationships.

Why Might Obesity and Asthma Be Connected?

Researchers have proposed several biological and physical explanations for the relationship.

Excess body fat can affect how the chest wall and lungs move, potentially increasing the effort required to breathe.

Obesity is also associated with changes in inflammatory signaling. These changes may interact with airway inflammation, although obesity-related asthma does not necessarily follow the same inflammatory pattern as allergic asthma.

Other proposed contributors include changes in the gut microbiome, shared genetic susceptibility, and metabolic disturbances.

The Israeli researchers examined asthma accompanied by allergic conditions and elevated blood eosinophil levels, a marker sometimes associated with particular forms of airway inflammation.

They found that associations involving allergic disease were generally weaker than those involving asthma overall.

Patterns involving eosinophils also differed between Arab Israeli and Jewish Israeli adolescents. However, blood testing was not consistently available, limiting the interpretation of these findings.

The study did not establish which biological pathways explain the association between obesity and asthma.

What the Results May Mean for Teenagers With Asthma

For teenagers living with both asthma and obesity, the findings reinforce the importance of managing respiratory symptoms while also addressing overall health.

Parents and teenagers can discuss several questions with their health care provider:

• Is the asthma well controlled? Frequent coughing, wheezing, nighttime symptoms, or difficulty participating in everyday activities may indicate that treatment needs reassessment.
• Are medications being used correctly? A clinician can review inhaler technique, prescribed treatments, and whether symptoms require frequent use of quick-relief medication.
• Have asthma attacks become more frequent? Repeated exacerbations, emergency visits, or courses of systemic corticosteroids may warrant a review of the asthma management plan.
• Can physical activity be maintained safely? Appropriate asthma treatment can help teenagers remain active. Exercise and nutrition plans should be individualized according to their health needs.

The study does not establish that losing weight prevents asthma or that weight reduction alone improves asthma control.

Teenagers should not stop or change prescribed asthma medications without consulting their health care provider.

Limitations

Despite its unusually large sample, the study has important limitations.

The most significant is its cross-sectional design. Researchers could not determine whether obesity developed before asthma or whether asthma contributed to subsequent weight gain.

The study also relied on recorded diagnoses, which may have included misclassification. Some adolescents with asthma may not have had the condition documented, while others may have received an asthma diagnosis without comprehensive testing.

Participants were included only if height and weight measurements were available. This could introduce selection bias if adolescents who received measurements differed systematically from those without measurements.

The researchers used each participant’s highest recorded BMI during the observation period, rather than a uniform measurement at a single age. This approach may not fully represent long-term weight patterns.

Medication purchases were used as indicators of treatment, but purchases do not establish whether medications were taken as prescribed.

The analysis also lacked consistent information on spirometry, detailed asthma control, treatment adherence, and several inflammatory markers.

Although researchers adjusted for selected demographic characteristics, unmeasured factors could still influence the observed associations.

Finally, the study involved adolescents enrolled in one Israeli health care organization, which may limit its generalizability to other populations.

Final Thoughts

A study of more than 600,000 Israeli adolescents adds to growing evidence that obesity and asthma are closely associated during childhood and adolescence.

The researchers found that teenagers with higher weight classifications generally had greater odds of asthma, with similar patterns among Arab Israeli and Jewish Israeli adolescents. Differences in corticosteroid use also raised questions about how asthma is managed across the two populations.

Earlier research suggests the relationship may work in both directions: obesity is associated with subsequent asthma diagnoses, while children with asthma may also be more likely to develop obesity.

For families and clinicians, the findings emphasize the value of monitoring asthma symptoms, reviewing treatment effectiveness, and addressing weight-related health concerns as part of comprehensive adolescent care.

Further research is needed to clarify the biological mechanisms connecting these conditions and determine which interventions produce meaningful improvements in respiratory health.

Funding and Disclosures

Treister-Goltzman and colleagues reported that their research received no specific grant from public, commercial, or nonprofit funding agencies.

The authors declared no known competing financial interests or personal relationships that could have influenced the study.

References

Black, M. H., Zhou, H., Takayanagi, M., Jacobsen, S. J., & Koebnick, C. (2013). Increased asthma risk and asthma-related health care complications associated with childhood obesity. American Journal of Epidemiology, 178(7), 1120–1128. https://doi.org/10.1093/aje/kwt093

Chen, Z., Salam, M. T., Alderete, T. L., Habre, R., Bastain, T. M., Berhane, K., & Gilliland, F. D. (2017). Effects of childhood asthma on the development of obesity among school-aged children. American Journal of Respiratory and Critical Care Medicine, 195(9), 1181–1188. https://doi.org/10.1164/rccm.201608-1691OC

Shan, L.-S., Zhou, Q.-L., & Shang, Y.-X. (2020). Bidirectional association between asthma and obesity during childhood and adolescence: A systematic review and meta-analysis. Frontiers in Pediatrics, 8, Article 576858. https://doi.org/10.3389/fped.2020.576858

Treister-Goltzman, Y., Menashe, I., & Nemet, D. (2026). Association between obesity and asthma among Arab Israeli adolescents compared with Jewish Israeli peers. Respiratory Medicine. Advance online publication. https://doi.org/10.1016/j.rmed.2026.109214