4 biggest risk factors for chronic disease, according to science

By Naveed Saleh, MD,MS
Published November 8, 2021

Key Takeaways

The majority of Americans struggle with chronic disease, according to the CDC. In total, 6 of 10 American adults have one of these illnesses, and 4 of 10 have two or more. Chronic disease refers to conditions that last 1 or more years and necessitate ongoing medical attention or limit activities of daily living.

Chronic diseases are a leading contributor to US healthcare costs, which amount to a staggering $3.8 trillion annually. The CDC identifies four main preventable risk factors in contributing to chronic disease: tobacco use, poor nutrition, lack of physical activity, and alcohol use. 

As a physician, it’s important to keep an eye on trends in these risk factors, in addition to counseling your patients on prevention. Here’s a look at recent findings covering these four risk factors.


The leading cause of preventable disease, disability, and death in the United States is tobacco use, with 34 million Americans smoking cigarettes. Moreover, 58 million nonsmokers are exposed to secondhand smoke. Each day, 200 Americans become daily cigarette smokers, and 1,600 youth puff their first cigarette.

Cigarettes lead to more than 480,000 deaths per year, with 41,000 deaths due to secondhand smoke. At least 30 Americans are living with serious smoke-related illnesses for every one person who dies of the habit.

About 14 of every 100 US adults aged 18 or older smoked cigarettes in 2019, with more than 16 million Americans living with a smoking-related illness.

On the bright side, smoking rates have decreased from 20.9% in 2005 to 14% in 2019, with the number of smokers who have quit going up, according to the CDC.

November is Lung Cancer Awareness Month, and physicians have an important role to play in advising patients on health risks related to smoking. Check out How doctors can take the shame out of smoking cessation counseling on MDLinx.

Poor nutrition

Fewer than 10% of US teens and adults eat enough low-energy-dense foods like fruits and vegetables, with 6 of 10 teens drinking a sugar-sweetened beverage every day and 5 of 10 adults also ingesting an excess of sugary drinks. Overall, US diets are high in added sugars, sodium, and saturated fats. 

Nutrition is a separate realm of health studies, the specifics of which may lie outside the wheelhouse of most physicians. In addition to consulting with registered dietitians or nutritionists about healthy eating patterns in your patients, the US government has developed Dietary Guidelines for Americans 2020–2025, which provide guidance for Americans at every stage of life.

The guidelines are broken down into four parts:

  1. Follow a healthy pattern of eating at every life stage—ie, from birth to 6 months, at about 6 months, and from 12 months until older adulthood (including pregnancy and lactation).

  2. Tailor and enjoy nutrient-dense food and beverage options that mirror personal preferences, cultural traditions, and financial considerations.

  3. Stay within calorie limits and meet food-group needs with nutrient-dense foods.

  4. Limit the intake of foods that are high in added sugars, saturated fat, and sodium, as well as alcoholic beverages.

Finally, research has shown that poor gut health can lead to certain chronic conditions. Read about that here.   

Lack of physical activity

More than 31 million Americans aged 50 years or older are inactive, which means that they engage in no physical activity beyond activities of daily living. Furthermore, only one of four US adults attains the recommended physical activity levels

In addition to contributing to heart disease, type 2 diabetes, cancer, and obesity, low levels of physical activity result in $117 billion a year in associated healthcare costs.

In a recent review article published in the Korean Journal of Family Medicine, the authors highlighted multifarious ways in which a sedentary lifestyle affects normal human physiology, including the following:

  • Reduces in lipoprotein lipase, muscle glucose, and  protein transporter activities

  • Impairs lipid metabolism

  • Decreases carbohydrate metabolism

  • Lowers cardiac output and systemic blood flow along with triggering of the sympathetic nervous system, thus decreasing insulin sensitivity and vascular function

  • Impairs insulin-like growth factor axis and the circulation levels of sex hormones, which heightens the risk of hormone-related cancers

  • Increases weight gain, adiposity, and elevates chronic inflammation markers, thus increasing the risk of cancer

  • Heightens levels of all-cause mortality, cardiovascular disease mortality, cancer risk, and risks of metabolic disorders such as diabetes mellitus, hypertension, and dyslipidemia

  • Increases the risk of other conditions such as dementia and cognitive impairment, as well as musculoskeletal disorders including arthralgia and osteoporosis

For related reading about exercise, check out Exercise myths debunked, on MDLinx.

Excessive alcohol intake

The excessive use of alcohol leads to 95,000 deaths in the United States each year, with 1 of 10 deaths in working adults due to alcohol misuse. Although binge drinking accounts for almost half the deaths due to excessive alcohol intake, 9 of 10 Americans who binge drink do not have a severe alcohol use disorder.   

In case you’re wondering, quarantining due to stay-at-home orders was linked to increased alcohol use during the pandemic. And that includes physicians and other medical professionals. By March 21, 2020, alcohol sales increased by 54% compared with those of a year before. Furthermore, the WHO issued a warning about the risk of alcohol exacerbating health concerns and risk-taking behaviors.

Results of a survey of American adults published in JAMA demonstrated that during the pandemic, alcohol was consumed 1 day more per month by three of four adults. Women also had a 0.18 day increase per month of heavy drinking, which translated to 1 extra day of heavy drinking per month for one of five American women. In these women, there was an increase in alcohol-related problems.

“In addition to a range of negative physical health associations, excessive alcohol use may lead to or worsen existing mental health problems, such as anxiety or depression, which may themselves be increasing during COVID-19,” wrote the authors. “The population level changes for women, younger, and non-Hispanic White individuals highlight that health systems may need to educate consumers through print or online media about increased alcohol use during the pandemic and identify factors associated with susceptibility and resilience to the impacts of COVID-19.

Click here to read about alcohol’s effects on specific chronic diseases such as stroke, ischemic heart disease, diabetes, liver cancer, and more.   

And finally, the above factors are not the only considerations for chronic disease prevention. Check out The link between sleep deprivation and chronic disease, on MDLinx.

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