India is facing a twin epidemic of diabetes and high blood pressure, doctors have warned, after the results of a countrywide study suggested that one in five people had both conditions.

The two-year study of nearly 16,000 adults in eight states found that 21 percent of patients with family doctors and consultants had diabetes and hypertension.

Just over a third (35 percent) had diabetes, while nearly half (46 percent) had hypertension, according to the Screening India's Twin Epidemic or SITE research, which was published on Monday.

Shashank Joshi, a consultant endocrinologist at the private Lilavati Hospital in Mumbai, said in a statement that the results indicated that the conditions "are indeed becoming a twin epidemic across the country".

He added: "What is even more worrisome is that 70 percent of the patients surveyed have 'uncontrolled' diabetes, including diabetics who are currently undergoing treatment.

"This figure not only demands immediate attention but also the implementation of necessary measures."

The research, backed by Aventis Pharma, a unit of French healthcare group Sanofi, also found that seven percent of diabetics and 22 percent of people with high blood pressure were unaware they had the condition.

According to the World Health Organization (WHO), diabetes affects some 346 million across the globe.

Both diabetes and cardiovascular diseases are affecting a growing number of people across Asia because of a combination of genetic factors, plus changing diets and a more sedentary lifestyle as a result of increasingly urban living.

The president of the Center for Diabetes, Obesity and Cholesterol Disorders in New Delhi, Anoop Misra, told AFP in April this year that India has the highest number of diabetics in the world at just under 51 million people.

But he warned that number could increase by nearly 150 percent in the next 20 years.