Unfit adolescents who have a high body mass index are more likely to suffer from hypertension when they are older than their peers, according to a new study from researchers at Stanford and Lund University in Sweden.
The paper, the first to discover this connection, was published today in JAMA Internal Medicine.
Lead author Casey Crump, MD, PhD, who recently left Stanford to join the Mount Sinai School of Medicine in New York, and his colleagues tapped a unique data source to uncover the relationship: the Swedish military. In the past in Sweden, all males had to join the military at age 18, and Crump and his team examined fitness and health records from more than 1.5 million military conscripts between 1969 and 1997. Thanks to the Swedish national health-care system, they were also able to obtain follow-up information to see when and if adults were diagnosed with hypertension.
I exchanged emails about the study with Crump, who is vice chair for research in the Department of Family Medicine and Community Health; below is our conversation.
Why did you decide to look at this?
Low physical fitness and obesity are very common, modifiable, and have an enormous public health impact.
What is the primary lesson from this work?
We found that both overweight/obesity and low aerobic fitness at age 18 were linked with higher long-term risk of hypertension in adulthood. Importantly, low aerobic fitness was a strong risk factor for hypertension even among those with normal body mass index (BMI). These findings suggest that interventions to prevent hypertension should begin early in life and include not only weight control but also aerobic fitness, even among persons with normal BMI.
Could you comment on the data you used?
We had the unique opportunity to examine standardized, objectively measured aerobic fitness and BMI information from a large military registry that included nearly all 18-year-old males in Sweden during 1969-1997 (from an era of compulsory military conscription). In addition, the Swedish national health-care system enables nearly complete ascertainment of outpatient and inpatient medical diagnoses for the entire population. This study would not have been possible without such rich data resources from a country with a universal health care system.
Are there any follow-up studies planned?
Our research group is also studying the effects of aerobic fitness, muscular strength, and BMI on other health outcomes, including diabetes, ischemic heart disease, and cancer. We hope that the findings will help inform earlier and more effective lifestyle interventions among children and youth to promote better population health in the U.S. and other countries.
Previously: The importance of knowing your blood pressure level in preventing hypertension, NIH-funded study shows effectiveness of intensive blood pressure management and Summer’s child: Stanford researchers use season of birth to estimate cancer risk
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