According to the results of a large and unprecedented international study, high Non-HDL/LDL that was responsible for an estimated 3.9 million worldwide deaths caused by IHD (Ischaemic Heart Disease) and stroke has changed dramatically, especially in the geographical location.

According to the Digestive Diseases Research Institute (DDRI) of Tehran University of Medical Sciences (TUMS) This important global study, entitled “ Repositioning of the global epicentre of nonoptimal cholesterol” that  conducted by Imperial College London In collaboration with a large number of researchers from the world Including  Iran led by Professor Majid Ezzati ,  has been published in June 3, 2020 in the journal  Nature 

This study  by using data from 1127 population-based studies ,  for the first time, examins the rate and trend of HDL (High –Density Lipoprotein) or good  cholesterol  and Non-HDL/LDL  (Low  Density Lipoprotein) or  bad cholesterol, changes in more than 102 million people aged 18 and over in 200 countries from around the world between 1980 to 2018.

Cholesterol is a waxy substance found in the blood. The body needs cholesterol to build healthy cells, but too much can lead to a build-up in the blood vessels and lead to clostrosclorosis. Cholesterol comes in different types. High-Density Lipoprotein (HDL) /good cholesterol, which should be 60 mg/dl or above, is thought to have a protective effect against heart attack and stroke, by mopping up excess bad cholesterol.

The results of this study are very important ,because high blood cholesterol is a serious risk factor for heart attack and stroke.
A previous global analysis reported trends in total cholesterol from 1980 to 2008, but did not analyse important lipid fractions  including HDL and Non-HDL cholesterol that are key to understanding the car- diovascular disease risk associated with non-optimal cholesterol.

The results of the study“ Repositioning of the global epicentre of nonoptimal cholesterol” :

Mean Total cholesterol  

Based on the results of this valuable study, In 2018, mean Total cholesterol (TC) was178 mg/dl for women and 174 mg/dl for men that has changed little In nearly four decades, by decreasing 1.16 mg/dl for women and 1.9 mg/dl  for men in every decade.

Mean HDL cholesterol

Also,  mean HDL cholesterol (High –Density Lipoprotein) / good cholesterol,   in 2018 was50.3  mg/dl for women and  42.5 mg/dl for men. The trend of this type of cholesterol has remained unchanged for women over the years and has decreased slightly in men.

Mean Non-HDL/LDL cholesterol

The results of this global study also show that the mean  Non-HDL/LDL (Low  Density Lipoprotein ) or  bad cholesterol  which is better to  be less than 70 mg/dl , in 2018 for both sexes, 128 mg/dl and 58 mg/dl more than usual. It remained unchanged from 1980 to 2018  (0.08 mg/dl decrease per decade)

Death rate due Non-HDL cholesterol in the world

According to the study , Non-HDL/LDL  (Low  Density Lipoprotein) or  bad cholesterol  was responsible for an estimated 3.9 million worldwide deaths from IHD (Ischamic Heart Disease) and stroke in 2017 that half of which occurred in East, Southeast and South Asia! Between 1990  to 2017, the number of these deaths increased by around 910,000 globally.

 significant changes in decline and increase of  blood lipids

This study shows that over the past four decades (39 years) there have been significant changes in decline and increase of blood lipids in different parts of the world: Non-HDL/LDL (bad cholesterol)  which was once a distinctive feature of rich western countries ,  by crossing  this region (especially northwestern Europe, North America and Australia) with a significant decline, has reached low-income and middle-income countries, especially in the East, Southeast Asia and the Middle East; where is not only  not decreased  in total cholesterol, but increased more than 3.9  mg/dl In every decade for both sexes (mostly related to Non-HDL/LDL).



Results for the world :

The ten countries with the highest Non-HDL/LDL in 2018 for women:

1.    Tokelau
2.    Malaysia
3.    Philippines
4.    Guyana
5.    Thailand
6.    Solomon Islands
7.    Myanmar
8.    Samoa
9.    Ecuador
10.    Indonesia

The ten countries with the highest Non-HDL/LDL cholesterol in 2018 for men:

1.    Malaysia
2.    Tokelau
3.    Thailand
4.    Lebanon
5.    Philippines
6.    Brunei Darussalam
7.    Serbia
8.    Tonga
9.    Lithuania
10.  Latvia

Professor Majid Ezzati

According to Professor Majid Ezzati, lead author and researcher in the study ,,Repositioning of the global epicentre of nonoptimal cholesterol,, for the first time, the highest levels of Non-HDL cholesterol are outside of the Western World.

He In response to the question: "Why has the trend and regional patterns of   blood lipids in the world has changed significantly? said : “High blood cholesterol is mainly due to dietary and behavioral factors, as well as Percentage of population under treatments with statin . All three factors have changed in the world over the past decades. Increased consumption of animal-based foods in low-income and middle-income countries, especially in East Asia,  which also faces the problem of overweight and obesity. In contrast, the replacement of saturated fats and trans fats with unsaturated fats in some high-income countries, in addition, the use of high blood fat-lowering drugs has been influential in these changes. ”

 lead author of the research from  Imperial’s School of Public Health reminded:  “The reduction in high blood cholesterol in high-income western countries even before the widespread use of statin drugs (reducing blood fats) and began in 1980. In contrast ,over the past four decades, consumption of animal-based foods, refined carbohydrates, palm oil, and sugar in Asia , Southeast Asia  and Middle East – where,  rate statins use are still low - has increased, unlike in high-income western countries. ”

He said : “The results of this study are very effective in determining population-based intervention policies to reduce high blood cholesterol - as a risk factor for cardiovascular disease - and increase attention to high-risk countries - especially in the Middle East and  Asia.”

Professor Reza Malekzadeh

Professor Reza Malekzadeh , the lead investigator of “the  Golestan Cohort ” , “The Persian Cohort ,,  and “ The Pars Cohort” studies  by announcing the participation of 80 researchers from 40 research centers affiliated to 35 Iran's universities of medical sciences  in this international study  "Repositioning of the global epicentre of nonoptimal cholesterol " which was Published in June 3, 2020 in the journal  Nature, considered Iran's information to be one of the strongest and most extensive data in this global study and the result of the most accurate and important study of Iranian blood lipids, which  was obtained  by testing more than 225 thousand healthy participants. ”

Deputy Minister of Health for Research , based on the results of the study of Iranian blood lipids in this global study, stated: “ Total cholesterol (TC) for Iranian men was 167 mg/dl and for women 174 mg/dl that these figures, compared to the last four decades, have remained almost constant and have not decreased significantly. ”

He added :“the level of " HDL cholesterol " (High –Density Lipoporotein) / good cholesterol  in Iranian men is 42.5 mg/dl and women is 48.7 mg/dl, which in 1980 was 41 mg/dl and 39 mg/dl   for men and women, respectively. ”

Distinguished professor of Tehran University of Medical Sciences (TUMS) described Iran as one of the countries with high levels of  Non-HDL/LDL (Low  Density Lipoprotein) or bad cholesterol  and said  : “ the level of Non-HDL/LDL in Iranian men is about 124 mg/dl and in women is about 120 mg/dl which are relatively stable over the past four decades. ”

Important role of Non-HDL/LDL Cholesterol  in premature deaths in Iran

Deputy Minister of Health for Research reminded  that “ half of the deaths in Iran are premature (under 70 years) ” and added : “ Heart attacks and strokes are the cause of half of the premature deaths in the country. Every year, more than 150,000 people die from heart attacks and strokes, and Non-HDL/LDL Cholesterol  play a key role in causing heart attacks and strokes and fatty liver. ”

According to Director of the Digestive Diseases Research Institute (DDRI),  high blood Cholesterol (Non-HDL/LDL) and "high blood pressure"  together, play a very important role in the occurrence of more than 40,000 premature deaths (under 70 years) and about 10,000 very premature deaths (under 50 years) in Iran.

Professor Malekzadeh added:  “In addition to hereditary and genetic causes, overeating, overweight and obesity, high-fat diets and high-carbohydrate diets , not having enough exercise, high salt intake, alcohol consumption, smoking, high consumption of red meat, low consumption of fresh fruits and vegetables and  increasing age are risk factors for high blood cholesterol. ”

He described  the strategy  for control of  high blood cholesterol as  choosing a healthy  lifestyle and proper diet, exercise and blood cholesterol test especially for high-risk individuals (people with a family history of premature death from heart attacks and strokes) and  said: “ all Iranians over the age of 35 should, In addition to measuring blood sugar, also have their blood pressure and blood lipids checked and treated if their levels  are high. ”

Distinguished professor of Tehran University of Medical Sciences (TUMS)  emphasized: “According to the latest global research, blood pressure above 12 on 8 abnormal and bad blood Cholesterol (Non-HDL/LDL) should be Under 70 mg/dl.”

He described the role of statins (high blood Cholesterol  lowering drugs) in controlling blood lipids as very important  and saide : “The results of scientific studies have shown that   statins prevent the world's  tens of  thousands of  heart attacks and strokes each year and also  controls the progression of fatty liver disease. ”

Director of the Digestive Diseases Research Institute (DDRI) added: “ one of the most effective drugs for controlling " high blood cholesterol" and " high blood pressure"  - which is based on published  research of  this institute (DDRI) and is now available in Iranian pharmacies - is the "polypill" . By taking  one tablet  "polypill" a day, " high blood cholesterol" and " high blood pressure"  could be prevented. ”

Writer : Fereshteh Hashemi

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