Hello, welcome everybody, this is doctor Bolad, board certified physician in cardiology, interventional
cardiology and internal medicine. I am here to help you with all the information you need
for your heart health and general health and informing you about all the latest treatments
in cardiology and medicine. If you are new to this channel, then definitely consider
hitting the subscribe button below and switch on the notification bell so you don’t miss
any new video that I post. For my international viewers outside the United States, you can
get translated subtitles for this video by pressing the closed caption – CC button
on the upper right part of your mobile device screen and selecting your preferred language
from the settings. Today I will talk to you about obesity and
its association with cardiovascular disease. I will talk in other videos about the benefits
of weight loss, in addition on how to achieve weight loss from a cardiologist's perspective.
Obesity is a progressing major public health problem creating a global health epidemic.
According to a World Health Organization report in 2016, obesity has nearly tripled since
1980 with 1.9 billion adults worldwide who are considered overweight, including 650 million
who were considered obese. Obesity has long been associated with an increased risk for
cardiovascular diseases. There are three main ways to measure obesity:
Number 1- Body mass index- BMI — This is the most practical way to evaluate the degree
of obesity and it correlates with cardiovascular disease and all-cause mortality. BMI is calculated
by dividing the body weight in kilograms by the square of the height in meters. Individuals
are classified as: ●Normal weight – BMI of 18.5 to 24.9 kg/m2
●Overweight – BMI of 25.0 to 29.9 kg/m2 ●Grade 1 obesity – BMI of 30.0 to 34.9
kg/m2 ●Grade 2 obesity – BMI of 35.0 to 39.9
kg/m2 ●Grade 3 or severe obesity – BMI ≥40.0
kg/m2 Number 2- Measurements of central obesity
— Waist circumference and waist-to-hip ratio are surrogate estimations of central adiposity,
which is linked to insulin resistance, dyslipidemia, and increased cardiovascular disease risk.
Central obesity is defined as either ●Waist circumference in men of more than
102 cm which is 40 inch and in women of more than 88cm which is 35 inch.
Or it can be a ●Waist-to-hip ratio in men of equal to or more than 0.90 and in women
of equal to or more than 0.85. Number 3- Body composition measurements — BMI
has clear limitations to discriminate between fat-free mass which is a protective factor,
and fat mass which is a factor associated with adverse outcomes. There is a role for
body composition assessment in obesity diagnosis but the implementation in clinical practice
is limited. To diagnose obesity, the American Association of Clinical Endocrinologists recommends
the use of body fat thresholds of >25 percent in men and >35 percent in women.
What are the Mechanisms of Cardiovascular Risk
Obesity leads to cardiovascular damage by promoting other risk factors to varying degrees.
There are a number of metabolic changes associated with obesity that may contribute to an increased
risk of cardiovascular disease: Insulin resistance and hyperinsulinemia — obesity
leads to insulin resistance and multiple metabolic and hemodynamic disorders, including hyperinsulinemia,
atherogenic blood lipid changes, hypertension, and type 2 diabetes. This is known as Metabolic
Syndrome. Patients who have metabolic syndrome have a threefold increased risk for developing
coronary heart disease and stroke. 2- Type 2 diabetes— This is strongly associated
with obesity in all ethnic groups. More than 80 percent of cases of type 2 diabetes can
be attributed to obesity, which may also account for many diabetes-related deaths.
3- Lipid abnormalities, including lower high-density lipoprotein level, higher triglyceride level
and high low density lipoprotein level. 4- Systolic and diastolic hypertension — Blood
pressure is often increased in obese subjects. In the Swedish Obesity Study, hypertension
was present at baseline in approximately one-half of subjects with obesity.
5 Left ventricular hypertrophy which is enlargement and thickening of the muscle of the heart.
Obesity is associated with volume overload which can lead to left ventricular hypertrophy,
which is associated with an increased incidence of heart failure, ventricular arrhythmias,
death following a heart attack and sudden cardiac death.
6- Obesity is associated with OBSTRUCTIVE SLEEP APNEA which is related to excess mortality,
hypertension, left and right ventricular dysfunction, inflammation, and arrhythmias.
7- Increased systemic inflammation – Obesity is independently associated with increases
in inflammatory markers that mediate the association with cardiovascular disease risk. C-reactive
protein (CRP) is the most extensively studied marker of inflammation in obesity and the
most widely used in clinical practice. 8- Sympathetic nervous system activation – This
has been observed in obesity and leads to high blood pressure.
9- Endothelial dysfunction – this is the inability of the endothelium to optimally
regulate vascular tone, hemostasis, and vascular inflammation. This can lead to cardiovascular
events, such as cardiac death, myocardial infarction, unstable angina and ischemic stroke.
What other conditions is Obesity associated with?
Obesity has been shown to be associated with: Increased Mortality, as shown in numerous
studies. For example in a prospective cohort study of over one million adults without a
history of coronary heart disease who were followed for 14 years, obesity was strongly
associated with an increased risk of all-cause mortality and cardiovascular death.
Increased incidence of coronary artery disease. For example, in the Munster Heart Study (PROCAM)
from Germany 16 thousand men and 7 thousand women were followed for up to seven years.
There was a graded positive relationship between the body mass index BMI and other coronary
heart disease risk factors and the increase of coronary heart disease death associated
with obesity was completely accounted for and mediated by these risk factors.
Heart Failure. Obesity leads to heart failure, especially heart failure with preserved ejection
fraction. In an analysis from the Framingham Heart Study, USA in which almost 6000 individuals
without a history of heart failure with a mean age of 55 years, were followed for a
mean of 14 years. The risk of heart failure was increased approximately twofold in subjects
with obesity compared with non-obese subjects. Atrial fibrillation – irregularity of heart
beating— This is the most common arrhythmia in adults in general. Several obesity-related
factors contribute to this irregularity of heart beating. In the Atherosclerosis Risk
In Communities study, it was estimated that one in five cases of atrial fibrillation can
be attributed to obesity. Sudden cardiac death — The most common cause
of death in obese patients is heart failure which occurs over a period of time, but there
is growing evidence of an increased risk of Sudden Cardiac Death in people with obesity.
Obese individuals are more likely to have prolonged QT intervals on the ECG heart tracing,
and this is thought to be a potential mechanism for sudden cardiac death in people with obesity,
in addition to the increased risk for coronary heart disease.
If you have any questions about what I presented to you today, or any medical question in general,
then subscribe to my channel and share your question in the comments section below and
I will reply to you. If you have a question that you would not like to share in public,
then subscribe to this channel, follow me on twitter @DoctorBolad, and then send me
a private twitter Direct Message and I will reply to you. Please like and share this video
with family and friends. This is Doctor Bolad, helping you with your heart health, thanks
for watching, and talk to you soon.