Increased consumption of junk food and more sedentary lifestyles have led to rise in the number of diabetes cases in the country, Indonesian Association of Diabetes Doctors head Sidartawan Soegondo said Sunday.

The association estimates there are around 14 million Indonesians between the ages of 25 and 45 with diabetes. This is particularly alarming, according to the group, because diabetes has traditionally affected much older people.

"Worse, these people show no symptoms, so when they start seeking treatment they already have heart or kidney problems that are caused by their diabetes," Sidartawan said during a media conference, as quoted by detik.com news portal.

Diabetes is seen as one of the major health threats of the 21st century. The World Health Organization estimates the number of people with diabetes worldwide will grow from 194 million now to 333 million by 2025 -- or more than 19,000 new patients every day for the next 20 years. Developing countries will bear the brunt of this growth. They are expected to have 238 million diabetes sufferers by 2025, or 71 percent of the total number of people with the disease worldwide. Indonesia currently has the fourth most number of cases in the world, behind India, China and the U.S. Diabetes -- an illness that occurs when the body lacks insulin, either because the pancreas does not produce any insulin or produces only a very small amount, or because the cells in the body are resistant to the insulin it produces -- is preventable. Once present, however, it is treatable but incurable, with complications that can lead to blindness and the amputation of limbs. The association said many Indonesians with diabetes fail to obtain regular check-ups, resulting in complications.

Early symptoms of diabetes are higher frequencies of eating, drinking and urinating, as well as difficulty sleeping. Sidartawan advised anyone who urinated frequently at night to go in for a check-up. "If you urinate more than three times at night, it is advisable that you check your sugar level so that problems can be prevented," he said. He added that diabetes was avoidable with a healthy lifestyle, such as cutting back on junk food and exercising. Before Sunday's media conference, around 1,800 people with diabetes took part in the "One Day, One Kilometer, One Purpose" march around the Senayan Sports Center in Jakarta.

The march was aimed at promoting exercise to help prevent diabetes.