Perils of flying economic class: Deep Vein Thrombosis or the “Economy Class Syndrome” By Shashi K. Agarwal, MD

The term ‘economic class syndrome’ was coined by Cruickshank and associates in the journal Lancet in 1988, describing an increased risk of deep vein thrombosis in the legs after a prolonged episode of air travel. It was suggested to be more common in the economy class due to its cramped quarters and the difficulty in frequent ambulation.

Subsequent studies have confirmed the increased risk for deep vein thrombosis with frequent and prolonged air travel. Pooled data from 3 studies reveal that the relative risk for DVT is 26% higher for each 2-hour increment of flight duration.

It is estimated that about 2 billion people travel by air each year. With the advent of long haul flights, travelers are often sitting for long periods of time. According to scientific studies, oral contraceptives, sitting in a window seat, advanced age and pregnancy increases DVT risk in long-distance travelers. The risk also appears to be higher in short people (<165 cm) or tall people (>185 cm), and those that are obese (BMI over 25 kg/m2).

Formation of a blood clot in the deep veins of the legs is commonly known as deep vein thrombosis or DVT. This can be symptomless or may result in pain, swelling, redness and warmth in the affected extremity. DVT is dangerous as the blood clot can dislodge and travel to the lung resulting in a serious medical emergency called pulmonary embolism or PE. PE can be fatal. Trauma, prolonged inactivity and conditions such as cancer, infections, and certain inflammatory and cardiovascular diseases increase the propensity to develop DVT.

Travelers can take some precautions to decrease the risk of DVT:

1. Stand, stretch and walk around the cabin every 2 hours.
2. Keep well hydrated. This includes limiting alcohol and coffee intake.
3. Wear loose clothing, especially from the waist down.
4. Perform foot, ankle and knee exercises (flex and extend) while sitting, every hour or so.
5. Walk at the airport during layovers.

People at high risk should also get professional compression stockings (providing 15-30 mm Hg pressure) or get one dose of low molecular weight heparin prior to a flight longer than 8 hours. Aspirin has shown no benefit in preventing deep vein thrombosis.

 

Inactivity: An Important Cardiovascular Risk Factor by Shashi K. Agarwal, MD

Cardiovascular disease (CVD) is the leading cause of death for both men and women in the United States. It is estimated that over a million Americans die of cardiovascular events each year. Although several risk factors for CVD are non-modifiable (age, male gender, race and family history), many are amenable to intervention. These include elevated blood pressure, abnormal blood sugar, high cholesterol, smoking, obesity, high fat and high calorie diet and excess stress. The American Heart Association (AHA) recommends that blood pressure be kept under 140/90, fasting blood sugar less than 110mg/dl, LDL cholesterol below 100 mg/dl, cessation of smoking, a body mass index of less than 25kg/m2 and eating a heart healthy diet. Moderate alcohol intake (less than 2 drinks per day) and low dose aspirin in high risk groups also protects against cardiovascular disease. Another modifiable behavior with major therapeutic implications is inactivity. AHA recommends all Americans partake in physical activity of at least 30 min/day on most days of the week, given its substantial health benefits.

Inactivity or a sedentary lifestyle is associated with increased cardiovascular events and premature death. Sedentary behavior, measured by television viewing time, has been associated with adverse cardiovascular health, increased obesity, diabetes mellitus, cancer and early death.(International Journal of Epidemiology. 2011;40(1):150-159)A review of several studies have confirmed that prolonged total sedentary time (measured objectively via accelerometer) has a deleterious relationship with cardiovascular risk factors, disease and mortality outcomes (Curr Opin Cardiol. 2011 Sep;26(5):412-9.)

The beneficial effects of exercise have been recognized in several occupational groups. Chair bound double decker bus drivers in London have more coronary heart disease than mobile conductors working on the same buses.( Lancet. 1953;265:1053-1057). Postal workers delivering mail by foot similarly have lower incidence of coronary disease than their office based colleagues.( Lancet. 1953;265:1111-1120). Railroad workers and longshoremen have reduced incidence of coronary heart disease compared to those in less active occupations. (Am J Public Health. 1962;52:1697-1707 and N Engl J Med. 1975;292:545-550.)

The beneficial effects of regular exercise is evidenced from several well recognized scientific studies. Leisure time exercise reduced cardiovascular mortality during a 16 year follow up of men with high risk of coronary heart disease in the MRFIT study. (Int J Sports Med. 1997;18 (suppl 3):S208-S215). In the Honolulu Heart Study, elderly men walking more than 1.5 miles per day similarly reduced their risk of coronary disease.( Circulation. 1999;100:9-13). Walking was associated with cardio-protection in the Nurses’ Health Study (N Engl J Med. 1999;341:650-658) and moderate activity in post menopausal women was similarly associated with a reduced risk of coronary disease in the Iowa Study (JAMA. 1997;277:1287-1292). People engaging in regular exercise also derive other desirable health benefits such as decreased rate of strokes, reduced incidence of cancer, decreased pain and stiffness in arthritis, improvement in erectile dysfunction and significant psychosocial benefits. There is also an increase in life span of about 3 years (Lancet. 2011;378:1244-1253. Epub 2011 Aug 16)

Regular physical activity helps reduce several cardiovascular risk factors: obesity, dyslipidemia, hypertension and diabetes mellitus. In patients with established cardiovascular risk factors, it helps prevent coronary occlusion and heart attacks. In patients with established coronary disease, it helps improve angina free activity levels and decreased death rates. In patients with heart failure, exercise improves heart function and quality of life. It also improves walking distance in patients with peripheral artery disease.

Therapeutic activity should incorporate range of motion exercises, resistance training as well as an aerobic workout. Aerobic exercise improves cardio-respiratory fitness, whereas resistance exercise training improves muscular strength. Together, they have salutary cardiovascular effects. Stretching exercises such as yoga reduce sympathetic activity and improve several other cardiovascular risk parameters. A varied mix of exercise regimens allow this therapeutic leisure activity to be enjoyable and ensures long term adherence.

The Centers for Disease Control and Prevention and the American College of Sports Medicine recommended in 1995 that all Americans target at least 30 minutes of moderate intensity physical activity on most, and preferably all days of the week. (Pate RR, Pratt M, Blair SN, et al. Physical activity and public health: a recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA. 1995;273:402-407.) Most professional guidelines continue to concur with these recommendations.

Sedentary lifestyle is an important cardiovascular risk factor. The benefit of regular exercise of moderate intensity and moderate duration in the prevention of cardiovascular disease remains irrefutable. Physical activity is an easy, cheap and effective way to avoid cardiovascular disease. And the benefits accrue, irrespective of the age of initiating an exercise program.

Being Tall: Good for Your Heart by Shashi K. Agarwal, MD

A strong link exists between stature and health. It has been associated with  imparied glucose tolerance, diabetes and complications of diabetes. It has also been linked with hypertension  and cardiovascular disease.

 The relationship between height and cardiovascular disease has been known for a long time. In a meta-analysis published in the European heart journal in 2010,  Paajanen and colleagues reported that shorter individuals were 50% more likely to develop or die from heart disease. They studied data from 52 studies comprising height and cardiovascular disease in a population totaling 3,012,747 individuals. The risk was higher if your height was under 5ft 4in or 165.4cm if you are a man or below 5ft or 153cm if you are a woman.

Cardiovascular risks associated with shorter stature include earlier and higher prevalence and greater severity of coronary artery disease, both in men and women. There is an increased risk for heart attacks, strokes and premature mortality. It is also associated with higher cardiovascular operative mortality.

 In the Physicians Health Study involving 1444 men being monitored for an average of 22 years, there was a 24% less incidence of heart failure in men over six feet when compared to men who were five feet, eight inches or shorter. This study from the Brigham and Women’s Hospital and Harvard Medical School in Boston was recently published online (January 2012) by the American Journal of Cardiology.

It has been suggested that a tendency for future cardiovascular morbidity and mortality may be influenced by factors affecting height and operating early in life. Also shorter people have smaller coronary arteries, which may allow them to get occluded earlier and predict a poorer operative mortality.

Are We Living Longer in the USA: CDC says YES! by Shashi K. Agarwal, MD

According to Wikepedia, “Life expectancy is the expected (in the statistical sense) number of years of life remaining at a given age.” It is generally quoted as the number of years a baby is expected to live at birth.  In 1900, global average life expectancy was just 31 years. By the mid mid-20th century, average life expectancy rose to 48 years.  In 2005, average life expectacy at birth reached 65.6 years. 

According to the CDC (CDC: “Deaths: Preliminary Data for 2010.”) the average life expectancy in America in 2010 has risen to 78.7 years, rising by about one month from 78.6 years in 2009. The death rate dropped to 746.2 deaths per 100,000 people, primarily due to a drop in deaths from cancer, heart disease, stroke, accidents, chronic lung disease, flu/pneumonia and blood infections. There has also been a drop in the infant mortality rates. 

Human life expectancy at birth has dramatically increased during the last century as the following data illustrates: 

Classical Greece: 28 years

Classical Rome: 28 years

Medieval Britain: 25-40 years

Early 20th century: 31 years

2010: 67.2 years 

Swaziland unfortunately still records an average of only 31.88 years in life expectancy while Japanese live to an average age of 82.6 years. 

Life expectancy differs from life span as calculation of life expectancy at birth includes all the babies that die before their first year of life as well as people that die from disease and war. The maximum life span for humans is said to be 122 years, referring to the oldest confirmed recorded age for any human (Jeanne Calment). 

According to the World Health Organization, global disease burden in 2030 worldwide will be ranked as follows:

1. HIV/AIDS

2. Unipolar depressive disorders

3. Ischemic heart disease

4. Chronic obstructive pulmonary disease

5. Perinatal conditions

6. Cerebro-vascular disease

7. Road traffic injuries

8. Cataracts

9. Lower respiratory infections

10. Tuberculosis

11. Hearing loss, adult onset

12. Diabetes mellitus

13. Diarrheal diseases

14. Violence

15. Malaria

Aspirin for Cardiovascular Protection: Only if You have Established Obstructive Vascular Disease! by Shashi K. Agarwal, MD

Cardiovascular disease is now the leading cause of morbidity and mortality worldwide. Over the last decade or so, prophylactic aspirin use has become a common practice to prevent cardiovascular events. Low dose aspirin is taken by millions of patients worldwide to prevent cardiovascular disease. However, recent reports have questioned its routine use in healthy adults as being cardio-beneficial.

A recent meta-analysis published online January 9, 2012 in the Archives of Internal Medicine revealed that although there is a modest benefit in taking aspirin for primary prevention, these advantages are offset by a higher incidence of non-trivial bleeding. In this analysis of nine randomized placebo controlled studies with 100,000 patients followed for six years, there was a 10% reduction in cardiovascular events but there was a 30% increased risk of significant bleeding events. (Seshasai SRK, Wijesuriya S, Sivakumaran R, et al. Effect of aspirin on vascular and nonvascular outcomes: meta-analysis of randomized controlled trials. Arch Intern Med 2012; DOI:10.1001/archinternmed.2011.628. Available at: http://archinte.ama-assn.org.)

Many other studies have shown that aspirin has a favorable risk/benefit ratio when taken for secondary prevention. Its regular use provides added protection in patients with an acute or previous  myocardial infarction or ischemic stroke, unstable or stable angina, stroke or cerebral ischemia, peripheral arterial disease, or atrial fibrillation.

Aspirin remains an important emergency treatment in suspected heart attacks. Given as chewable ‘baby’ aspirin in a dose of 160 mg to 325 mg, it is very effective in slowing platelet aggregation in patients with  an acute coronary syndrome. (recommended by the American Heart Association and the American College of Cardiology)  Its emergent use helps  prevent further occlusion or reocclusion of the coronary artery, thereby reducing myocardial damage and death. Previous studies have demonstrated  a 23% reduction in death in patients with suspected heart attack, and a 49% reduction in non-fatal heart attacks and strokes. An even more impressive 53% reduction is seen with its use in the incidence of myocardial infarction, stroke of vascular death following coronary angioplasty. 

Final recommendations: Do not use aspirin for primary prevention of cardiovascular disease. However aspirin 62-150 mg has evidence based benefits in the secondary prevention of cardiovascular disease. It also has dramatic beneficial effects if used in the chewable form in suspected heart attacks.

Nuts about Nuts? The Best Nuts for Cardiovascular Protection by Shashi K. Agarwal, MD

Cardiovascular disease is now the leading cause of morbidity and mortality worldwide. Dietary indiscretion is emerging as an important villain in its development. Besides a diet rich in fruits, vegetables and whole grains, regular nut consumption has shown to impart significant beneficial effects in reducing cardiovascular risk.

Nuts contain healthy mono and polyunsaturated fatty acids, alpha linolinic acid, fiber and beneficial bioactive compounds such as phytosterols. Ingestion results in a decrease in low density lipoprotein, prevention of LDL oxidation, reduction in inflammatory markers of cardiovascular disease and improved endothelial function. These beneficial effects translate into a lower atherosclerotic disease risk and thereby reduced coronary artery disease. Other benefits include increased insulin sensitivity and improved weight management.

A recent study looked at various raw nuts and rated them according to their polyphenol content and potency. The descending ranking from the best raw nuts: walnuts, brazil nuts, pistachios, pecans, peanuts, almonds, macadamia nuts, cashews and hazelnuts. Among roasted nuts, the descending order was: walnuts, brazil nuts, hazelnuts, peanuts, pecans, cashews, macadamia nuts, almonds and finally pistachios.

To summarize, regular consumption of nuts, especially walnuts and brazil nuts, can help minimize cardiovascular risk and also decrease the risk of developing type 2 diabetes mellitus.

Prevent Cancer with Lifestyle Changes by Shashi K. Agarwal, MD

Four common lifestyle factors are responsible for the majority of cardiovascular diseases in the world —  tobacco, diet, alcohol, and obesity. However, cancer has now replaced cardiovascular diseases as the number one killer in that country. If this is an indicator of things to come, the number one killer in the developed world will soon be cancer.

A recent report from the Queen Mary University, London, United Kingdom, suggests that the same four lifestyle factors are also responsible for about 40% of all cancers. In a comprehensive review of cancer and lifestyles, published in a supplement to the December issue of the British Journal of Cancer, Dr. Max Parkin suggests that about 40% of all cancers can be prevented by following a healthy lifestyle. Tobacco was the major risk factor in both men and women- attributing to 23% risk in men and 25.6% risk in women.  Other risk factors in men were inadequate intake of fruits and vegetables (6.1%), occupational exposure to cancer causing chemicals such as asbestos (4.9%), excessive alcohol intake (4.6%), overweight and obesity (4.1%) and excessive sun exposure and sunbeds (3.5%). In women the risk factors were overweight and obesity (6.9%), infections such as human papillomavirus infection or HPV (3.7%), excessive sun exposure and sunbeds (3.6%), lack of fruits and vegetables in the diet (3.4%) and excessive alcohol intake (3.3%).

For certain cancers, such as lung cancer, lifestyle factors accounted for 89.2% of all cases.

Both men and women have the power to change these lifestyles and decrease their risk of cancer by almost 40%.

Do Low Vitamin D Levels Correlate With Osteoporosis?

Do Low Vitamin D Levels Correlate With Osteoporosis?
Shashi Agarwal, MD, FACC, East Orange, NJ; Neil Argarwal, Edison, NJ

INTRODUCTION: Osteoporosis is related to many factors, including a
family history of the disease, tobacco use, steroid use, major preexisting
medical diseases and vitamin D deficiency. This retrospective study was
done to see if low vitamin D levels correlate with the presence of
osteoporosis.

METHODS: We reviewed the records of 101 consecutive
patients who had DXA scans and vitamin D levels done over the period
of one calendar year. Bone mineral density was measured at the hip and
spine by dual-energy X-ray absorptiometry. T scores were considered
normal between +1 and -1, osteopenia between -1 and -2.5 and
osteoporosis if lower than -2.5. Vitamin D was measured as serum 25-
hydroxy vitamin D by the DiaSorin ICMA method. Vitamin D levels were
categorized as: normal levels: 30ng/ml or higher; mild deficiency:
20ng/ml-29ng/ml; moderate deficiency: 10ng/ml-19ng/ml and severe
deficiency: 0ng/ml-9ng/ml.

RESULTS: Of the 101 patients (ages 20 to 88
years) [54 (53.5%) males; 47 (46.5%) females], 19 (18.8%) had normal
vitamin D levels and 82 (81.2%) had low levels. Of the 19 with normal
levels, 6 (31.6%) had normal DXA scan, 8 (42.1%) had osteopenia and 5
(26.3%) had osteoporosis. Of the 82 with low vitamin D levels, 39
(47.6%) had normal DXA scans, 32 (39.0%) had osteopenia and 11
(13.4%) had osteoporosis. Of the 28 with mild deficiency, 12 (42.9%)
were normal, 13 (46.4%) were osteopenic and 3 (10.7%) were
osteoporotic. Of the 50 with moderate deficiency, 27 (54.0%) were
normal, 17 (34.0%) were osteopenic and 6 (12.0%) were osteoporotic.
Of the 4 with severe deficiency, 0 (0.0%) were normal, 2 (50.0%) were
osteopenic and 2 (50.0%) were osteoporotic. The average age of those
who were normal was 52.59 years, those with osteopenia was 56.38
years, and those with osteoporosis was 57.91 years.

CONCLUSION: We
found that approximately one half of the patients with mild or moderate
vitamin D deficiency had evidence of either osteopenia or osteoporosis
on DXA scanning. All patients with severe deficiency were osteopenic or
osteoporotic. Osteoporotic patients tended to be older. However, there
was no diagnostic correlation between low vitamin D levels and the
presence of osteoporosis.

Presented at the Family Medicine Forum 2011, Montreal, November 2011

Vitamin C and the Cardiovasular System: Shashi K. Agarwal, MD

A recent study presented at the American Heart Association’s Annual Meetings in Orlando in November, 2011 showed that there was an inverse relationship between vitamin C levels and an increased risk of development of heart failure. This study examined otherwise healthy 9,187 men and 11,112 women aged 39 to 79 years participating in the “European Prospective Investigation into Cancer and Nutrition”. Their plasma vitamin C concentrations were correlated with incident fatal and non-fatal heart failure events. During a mean follow up of 12.8 years, Dr Roman Pfister and co-researchers from Europe found that for every increase of 20 μmol/L (1 SD) in plasma vitamin C concentration, there was an associated 17% relative decrease in risk for heart failure.

Two previous major studies have found no cardio-protective effect of vitamin C supplementation. In the Physicians’ Health Study II, supplementation with 500 mg of vitamin C every other day in 14,641 US male physicians over the age of 50, was compared with placebo. After 8 years of follow up, vitamin C did not have any beneficial effect on total mortality, heart attacks, stroke or cardiovascular disease death. This study was published in the Journal of the American Medical Association in the November 12, 2008 issue.

In another study involving 8171 women with a mean age of 60, during a follow up of 9 years, no overall benefit from vitamin C was observed for prevention of cardiovascular events. This study was done by Brigham and Women’s Hospital in Boston, with the results published in the August 13, 2007 issue of Archives of Internal Medicine.

Since vitamin C is an antioxidant, there has been great excitement regarding its potential cardio-protective effects. Oxidative stress is closely linked to the development of atherosclerosis and its major complications – heart attacks and strokes. Vitamin C has been primarily used to prevent scurvy. It is also beneficial in preventing gout by reducing serum uric acid levels. Its role in preventing common colds has not been scientifically validated.

Vitamin C is a water-soluble vitamin, with almost 90% of our intake coming from fruits and vegetables, especially citrus fruits, peppers, broccoli, and tomatoes. Kakadu plum, camu camu fruit and rose hips contain extremely high concentration of this vitamin. Vitamin C is also present in some cuts of meat, especially liver and raw oysters. In the United States, vitamin C supplements are widely used. It is available in a variety of forms, including pills, drink mixes and crystals, either naked or in capsules. However a review all the major studies on vitamin C and cardiovascular disease, demonstrates no scientific confirmation that nutritional supplementation with vitamin C is heart protective

Levels of plasma vitamin C correlate consistently with fruit and vegetable intake  and an increased intake of fruit and vegetables is associated with a significant increase in plasma vitamin C concentration. Since studies with vitamin C supplementation provide no support for cardiovascular protection and studies using vitamin C levels as a biomarker for fruit and vegetable intake appear to show distinct cardiovascular benefit, the ‘writing’ is on the wall – do not eat nutrients but eat foods rich in nutrients – namely plenty of fruits and vegetables. The cardiovascular benefits of fruit and vegetable intake may not be limited to vitamin C, as there are many other nutrients in fruits and vegetables, such as potassium and magnesium, that also have positive effects on the heart.

The North American Dietary Reference Intake in 2008 recommended 90 milligrams of vitamin C per day and no more than 2,000 milligrams per day. Toxicity is however rare, as excess intake is not absorbed, and excesses in the blood rapidly cleared in the urine.

ABO Blood Group – A Cardiovascular Connection: Shashi K. Agarwal, MD

Cardiovascular disease is now the number one killer in the world. Although the major risk factors such as hypertension, diabetes mellitus, hypercholesterolemia, obesity, physical inactivity and smoking are well known, some minor risk factors remain relatively unknown. The ABO blood group is one such minor risk factor.

Austrian scientist, Karl Landsteiner earned a Nobel Prize for the discovery of the ABO blood group system in 1901.  Inherited antigenic substances on the surface of the red blood cells allow a classification of the blood into different groups (blood type). Lawyers soon started using this in paternity suits, police in forensic science and anthropologists in the study of different populations. The Japanese, started believing that a person’s blood type is predictive of their personality, character and compatibility with others. Its major impact however, was in preventing fatal reactions to blood transfusions.

If transfusion is given without proper typing and cross-matching, naturally occurring antibodies in the recipients blood can bind to corresponding antigens on the transfused red blood cells resulting in an acute hemolytic transfusion reaction that can cause widespread intravascular blood clotting, shock, acute renal failure, and death.

Another major health impact was understanding the patho-physiology behind the hemolytic disease of the newborn. This dangerous reaction occurs as the anti A and anti B antibodies produced in the O blood group mother cross the placenta and enter the blood stream of her infant with type A or type B blood. However, due to lower number of fetal antigens, the reactions are usually less severe.

Recent reports have noticed an interesting connection of these blood groups with cardiovascular disease. In a presentation at the Annual Scientific Meetings of the American Heart Association in November 2011, researchers from the Harvard School of Public Health reported that men and women in the AB blood group had a  26% higher risk of developing stroke when compared with those with type O blood. Women with type B had a 15% higher risk of stroke, when compared with those with type O blood. They analyzed data from two major studies – the Nurses’ Health Study (NHS) which included 61,973 women and the Health Professionals Follow-up Study (HPFS) which included 27,808 men. The follow up was 26 years and 20 years.

In a study published in the New England Journal of Medicine in the December 9, 1971 issue, researchers investigating  10,000 Israeli male government employees 40 years of age and over as part of the Israeli Ischemic Heart Disease Project (five year duration) found that subjects with blood Groups A, B, and AB tended to have higher incidence rates of myocardial infarction than those with other blood groups. High rates were also noted in A and B subjects for angina pectoris. Subjects in blood Group O tended to have lower rates of infarction and angina pectoris than those of other groups.

Researchers reported a higher incidence of elevated cholesterol levels and ischemic heart disease in non-O group individuals in the British Medical Journal in June 1990. The results emanated from a prospective study of 7662 men with known blood groups. Many other studies have similarly found increased heart attacks in non-O blood group individuals.

In another study published in the February 2009 issue of the Journal of Thrombosis and Haemostasis, researchers reported a higher tendency for arterial and venous clotting in patients with non-O blood groups. Several studies have demonstrated the influence of the ABO blood group on plasma levels of von Willebrand factor. VWF is major player in blood clotting.

In summary, non-O blood group individuals suffer a higher risk of myocardial infarction, angina, cerebral strokes and venous thrombo-embolism than those with group O blood. This increased risk, although real, is not very significant. Since your blood group cannot be changed, non-O blood group people should follow heart healthy lifestyles more judiciously, to nullify any increased genetic risk conferred by their blood type.