High Blood Pressure Is The Leading Preventable Cause Of Premature Death In China

An article published Online First and in a future edition of The Lancet reports that high blood pressure (hypertension) causes more than 1 million premature deaths in China, and over 2 million total deaths. This makes it the leading preventable cause of death in the country. It is essential for the Chinese government to focus on prevention and control of hypertension, and make it its top public health priority. Primary prevention will be a vital tool in such efforts. This includes reducing the enormous average daily salt intake and lifestyle modification. The article is the work of Prof Jiang He, of the Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA, and colleagues.

In 2000, it was estimated that 972 million adults, or 26.4 percent of the world's adult population, had hypertension. In 2025, the number of adults with hypertension is predicted to increase by 60 percent to 1.56 billion. However, these estimates do not include pre-hypertension which is a slightly raised blood pressure that does not qualify as 'full' hypertension. The authors in this study estimated premature deaths attributable to increased blood pressure in China. They studied a nationally representative sample of around 170,000 Chinese adults aged 40 years and older. At a baseline examination in 1991, blood pressure and other risk factors were measured. Follow-up assessment was done in 1999 and 2000. Premature death was defined as mortality before age 72 years in men and 75 years in women since those were the average life expectancies in China in 2005.

Hypertension and pre-hypertension were significantly linked with increased all-cause and cardiovascular mortality. In 2005, an estimated 2.3 million cardiovascular deaths were attributable to increased blood pressure in China including 2.1 million in adults with hypertension and 0.2 million in adults with pre-hypertension. Also, 1.3 million premature cardiovascular deaths were attributable to raised blood pressure in China including 1.2 million in adults with hypertension and 0.1 million in adults with pre-hypertension. Most blood pressure-related deaths were caused by cerebrovascular diseases with 1.9 million of total deaths and 1.1 million of premature deaths.

The authors explain: "Our results show that raised blood pressure is the leading preventable risk factor for premature deaths in China... The enormous mortality burden related to blood pressure that we have documented is striking and unexpected compared with previous estimates."

The researchers underline the fact that the prevalence of hypertension is high and increasing in the Chinese population. On the other hand, the proportion of awareness, treatment, and control is low. An earlier national survey indicated that approximately 153 million Chinese adults aged 18 years or older met criteria for diagnosis of hypertension. Only 24 percent of them were aware of their condition and 19 percent were receiving antihypertensive drugs. It is alarming that adequate control of blood pressure (<140/90 mm Hg) was achieved only in 24 percent of patients receiving treatment or less than 5 percent of all hypertensive patients.

The authors comment: "Dietary sodium intake is very high in China, so lifestyle modification, especially reduction of dietary sodium, should be an effective approach for primary prevention. The enormous burden of mortality attributable to blood pressure calls for a national policy to emphasise prevention and control of hypertension as the top public health priority."

They write in conclusion: "Traditionally, infectious disease prevention and control has been the public health priority. Our results suggest that mortality attributable to blood pressure is the major public health challenge and argue for shifting of public health priority and resources towards prevention and control of hypertension. Prompt action will save millions of lives each year."

In a supplementary note, Professor Stephen MacMahon, The George Institute, University of Sydney, Australia, and Professor Lijing Yan, The George Institute China, Peking University Health Science Center, Beijing, China, call attention to the importance of the recently established Global Alliance for Chronic Disease and the new China Rural Health Initiative in helping China's battle with chronic disease. They highlight the significance of the use of cheap intervention packages that can reach all of China. These include reduced sodium cooking salt and low cost treatments including generic antihypertensive drugs.