A STUDY has found that cholesterol levels in Hongkong are higher than in the United States, sparking fears of an epidemic of heart disease in future. The study, by Hongkong University, also found that one quarter of the territory's people have significantly high cholesterol levels, putting them at high risk of developing heart disease. Study leader Dr Fong Ping-ching said heart disease was now the second biggest killer in Hongkong. The findings have shocked an Oxford University heart disease expert and triggered calls from local physicians for a ''heart disease authority'' to co-ordinate action to lower cholesterol levels in the territory. They said this should include a massive campaign to instil healthy diet and lifestyle habits among children, to reverse the increase in heart disease rates. ''It's really very frightening to see the sorts of cholesterol levels found in Hongkong, which exceed the levels found in the US,'' said Dr Anthony Keech, co-ordinator of the Oxford Cholesterol Studies at Oxford University. With high cholesterol levels strongly linked to heart disease, Hongkong would probably begin seeing the same high heart disease rates as the US - something Chinese communities traditionally did not suffer from, he said. ''The Hongkong population is Westernising not only its cholesterol levels but probably its heart disease rates too,'' said Dr Keech, who is in Hongkong to address a medical symposium on the issue. Dr Fong said Hongkong's fat-laden diet was to blame. ''It's mainly due to the Westernisation of the diet,'' he said. ''People are eating more fat, more meat. At the same time, they are cutting down on carbohydrates and vegetables.'' He said eating out often was also a factor, as restaurant food was likely to be more fatty. The study, the most up-to-date and comprehensive local research on the issue, began in 1991 at Hongkong University's Department of Medicine and Queen Mary Hospital's Department of Clinical Biochemistry. It examined the level of fatty deposits in the blood of about 700 adults aged 20 and above. The study indicated that almost 60 per cent of the population had higher cholesterol levels than was desirable. The overall level was 5.47 mmol/L (millimole per litre, the unit measuring cholesterol density per litre of blood), compared to the US average of 5.3 mmol/L. The ideal level is 5.2 mmol/L. About 25 per cent of people had very high levels - 6.2 mmol/L or above. This compared badly with Hongkong's 1950s average level of 3-4 mmol/L, and even worse with levels of less than 3 mmol/L in parts of rural China. Dr Fong said middle-aged men and the elderly were most at risk. About one third of men over 50 had very high cholesterol levels and almost half of the men in their 60s had borderline high levels. Women's levels were low until after the menopause, when high risk levels shot from 14.0 per cent of 40-year-olds, to 55 per cent for those in their 60s. Dr Fong said people could reduce cholesterol levels by changing their diet and lifestyle, although a few might need medication. But a serious effort to reduce heart disease in Hongkong would require government involvement, he said. He called for an independent authority to lead public education and treatment efforts, targeting children in particular. ''It is difficult to target the dietary pattern of adults but eating patterns are formed in childhood,'' he said. A Health and Welfare Branch spokesman said it planned to step up the campaign against heart disease.