Global Public Health Crises of Obesity and Hypertension: Importance of Prevention and Treatment of Obesity

According to a report from the World Health Organization (WHO), approximately 1.1 billion people worldwide have hypertension with prevalence of 1 in 4 men and 1 in 5 women.¹ Notably, one of WHO’s global targets is to reduce hypertension by 25% between 2010 and 2025. In the United States (U.S.), the prevalence is higher with 45% of adults having hypertension.² The absolute burden in the U.S. has also increased from 87 million adults in 1999-2000 to 108 million in 2015-2016.³ Hypertension prevalence also increases with age with 54.5% prevalence in adults aged 40–59 and 74.5% in adults aged 60 and over. In 2018 alone, hypertension was a contributor to nearly half a million deaths in the United States.⁴

Association between obesity and hypertension have been well described.⁵ Data from population-based studies showed nearly linear relationship between body mass index (BMI) and blood pressure.^6,7 Findings from the Framingham Heart Study showed that 78% of essential (primary) hypertension in men and 65% in women can be attributed to obesity.⁸ Unfortunately, worldwide prevalence of obesity has almost tripled since 1975 according to a WHO report. In 2016, >1.9 billion adults (39%) were classified as overweight, and among those >650 million (13%) were obese.⁹ In the U.S., the prevalence of obesity is even higher with 42% of adults classified as obese in 2017-2018, an increase from 30% in 1999-2000.¹⁰ Given the strong association between obesity and hypertension, we should expect a continued rise of hypertension prevalence in the United States and the world in the future.

Association between obesity and hypertension is at least partially mediated by fat depot distribution. Increased deposition of visceral fat is associated with increased risk of hypertension compared to other fat depots, including subcutaneous and lower body fat.^11,12,13 Aerobic exercise has been shown to reduce visceral adiposity.¹⁴ Similarly, combination of endurance and strength training has also been shown to decrease visceral fat while increasing muscle mass.¹⁵ However, to this date, no large study has been performed to link this reduction of visceral adiposity by exercise and its association with improvement/prevention of hypertension. Among drugs approved by the Food and Drug Administration (FDA) for weight loss, orlistat has been shown to have the greatest reduction in visceral fat, with a mean reduction of 67 cm².¹⁶ As mentioned in the Statement, orlistat, which reduces intestinal fat absorption, was associated with 3% decrease in body weight and decline in blood pressure which could be mediated by reduction in visceral adiposity. Liraglutide, a centrally acting drug which increases satiety, also demonstrated reductions in body weight, blood pressure, and visceral fat.^17,18 Interestingly, while its weight loss effect has not been described, combination of empagliflozin and metformin have been shown to reduce visceral fat as well.^16,18 Future clinical trials are needed to create more approaches that treat and prevent hypertension by targeting visceral adiposity.

In addition to the medications mentioned previously, many other drugs have been approved by the FDA for weight loss: phentermine, diethylproprion, phendimetrazine, and benzphetamine for short-term use; phentermine/topiramate extended release, and naltrexone/bupropion for long-term use. Despite these options, only around 1% of eligible patients were prescribed weight loss pharmacotherapy in the U.S.,^19,20 which is an abysmally low prescription rate of a treatment of a disease that is ravaging the country and the world. Additionally, 24% of prescribing providers account for 90% of filled prescriptions. While these drugs are not strikingly effective and certainly are not free of adverse effects, even a slight increase of prescription rate would likely have a non-trivial effect on the prevalence of obesity and hypertension in the U.S. and the world. Metabolic surgery appears to be a more effective approach in reducing obesity and hypertension. Systematic reviews of observational data and The Gastric Bypass to Treat Obese Patients with Steady Hypertension (GATEWAY) trial showed that metabolic surgery was superior to medical therapy in controlling blood pressure and reducing weight with a relatively durable result.^21,22 With improvement in surgical techniques, the contemporary complication rate of metabolic surgery is similar to routine surgeries such as laparoscopic cholecystectomy or appendectomy.²³ Yet, similar to drugs, in 2017 only approximately 1 percent of eligible patients underwent metabolic surgery.²⁴ Future studies are needed to definitively determine long-term safety and efficacy of these approaches and to further elucidate factors influencing the beliefs of patients and healthcare providers regarding these approaches. Public health campaign would likely be needed in the future as well.

Lifestyle interventions which include exercise, physical activity, and dietary modification are effective strategies in reducing body weight and blood pressure as described in the Scientific Statement. While they should always be an integral part of weight loss strategy given its lack of significant adverse effects and low cost, lifestyle interventions are subject to recidivism which significantly reduce the beneficial effects of weight-loss on blood pressure over time, and much of it is related to weight regain.²⁵ Weight-loss maintenance requires high levels of physical activity and continued dietary modification.²⁶ There are public health interventions that can “nudge” an individual’s physical activity level by strategic planning and zoning of public spaces which could limit traffic to make walking and cycling safer, improving public transportation, or building schools and shops within walking distance of neighborhoods.^{27, 28} Just as importantly, we need to increase our effort in preventing and reducing childhood obesity. A systematic review and meta-analysis found that school-based interventions are effective in preventing childhood obesity.²⁹ A renewal and reinforcement of programs like “Let’s Move!” that was led by former First Lady, Michelle Obama, can help this critical goal of decreasing childhood obesity.³⁰ This Scientific Statement provides a timely and comprehensive review of identifying the mechanisms obesity-related hypertension and describing current and future strategies of prevention and treatment of obesity and hypertension.