Lau Yu-lung

1. Population and Vital Statistics¹

The estimated mid-year population of Hong Kong in 1996 was 6.3 million, living in a total area of 1095 square kilometres. The overall population density was 5,780 people per square kilometre, with the highest density in Kwun Tong District at 53,610 people per square kilometre.

As a result of decreasing birth rate and increasing life expectancy, Hong Kong's population has been ageing as in developed countries (Fig. 1). The median age of the population in 1996 was 34 years old with 18.5% under 15 and 10.1% over 64 years old. By the year 2000, it is estimated that 10.6% of the population will be aged 65 and over, and by 2010, 11.3%. Most of the population is of Chinese descent (95%).

Fig. 1 Population Pyramid, 1976 and 1996

2. Health Statistics¹

The average life expectancy at birth has been steadily increasing for more than three decades, reaching 76.3 years for males and 81.8 years for females in 1996 (Fig. 2).

Infant mortality rate has also decreased throughout the years, reaching 4.0 per 1,000 live births in 1996. Maternal mortality rate remained low at 3.1 per 100,000 total births (Fig. 3).

The absolute number and rates of live births and deaths over the last 50 years are shown in Table 1 and 2. These figures show the continuous improvement in our population health status.

Fig. 2 Life Expectancy at Birth (Male and Female), 1976-1996

Fig. 3 Infant Mortality Rate and Maternal Mortality Rate, 1976-1996

Fig. 4 Ten Leading Causes of Deaths, 1996

3. Major Health Problems¹

For the whole population, chronic degenerative diseases constitute the major causes of death in Hong Kong. The top four killers were malignancy, cardiac diseases, pneumonia and cerebrovascular disease in 1996, representing 68.8% of all deaths. They were followed by injury and poisoning (Fig. 4).

However it was quite different for the children. The major cause of death in 1996 for under 1 year old was congenital anomalies, while for those 1-14 years old was injury and poisoning (Table 3, 4, 5).

The General Household Survey conducted in 1996 found that 267 males and 31 females per 1,000 persons of the respective sex above the age of 15 were daily smokers. A continuous drop in overall smoking prevalence was noted (Fig. 5). Yet, a rising trend was seen in women, except for those aged 60 and above. The rate of smoking among females rose from 2.7% in 1993 to 3.1% in 1996. Another worrying trend is the increasing exposure to smoking among school children. A survey in 1994 showed that the smoking experience (ever-smoking) of Form One students was 21%, rising to 37% in Form Three students.² The tobacco industry is targetting their advertisements to young persons and women.

Despite very enviable measures of health among the population as evidenced above, other parameters indicate there are still lots of room for improvement in Hong Kong. For example, the incidence of tuberculosis in Hong Kong is still ten times that of developed countries, at about 110 per 100,000 population (Fig. 6). Outbreaks of communicable diseases still occur from time to time, the most famous being the "Bird Flu" infection due to avian influenza A subtype H5N1 from May 1997 to January 1998.^3-4 Eleven of the eighteen patients were children and the overall mortality was 33%. This outbreak led to a complete restructuring of how Hong Kong should deal with food hygiene issues by the government.

* Data were obtained through the General Household Surveys in 1982, 1983, 1984, 1986, 1988, 1990, 1993 and 1996 "Modified from Reference 1"

Fig. 5 Smoking Prevalence*, 1982-1996

"Modified from Reference 1"

Fig. 6 Notification and Death Rates of Tuberculosis, 1976-1996

The most common single-gene inherited disease in Hong Kong is thalassaemia, with an overall carrier rate of 8.4%.⁵ In a recent survey of 1800 high school students, 5% of these students were found to be carriers of α-thalassaemia and 3.4% were β-thalassaemia carriers or with mutation encoding for haemoglobin E. Another common single-gene disorder is G6PD deficiency which is of X-linked recessive inheritance, with 4.4% males affected.

Allergic diseases, such as asthma, seem to be rising in incidence as in other developed countries. A recent survey of 3,618 6- to 7-years-old children revealed 9.2% of the children experienced wheeze in the past 12 months and a much higher wheeze-ever prevalence at 16.8%.⁶ Some infectious diseases which were common in the developed West might not be as prevalent in Hong Kong, such as Haemophilus influenzae type b (Hib). However the apparently low prevalence of Hib disease at 2.7 per 100,000 under 5-year-olds could be due to widespread abuse of antibiotics and other factors still not clear.^7-8 There is still no universal Hib vaccination offered in Hong Kong.

4. Child Health Care Provision

The child health care in Hong Kong is still not integrated. The private paediatricians provide mainly the primary care with the public hospital paediatricians the secondary and tertiary care. The Department of Health is responsible for public health issues, such as immunisation, newborn screening for hypothyroidism and G6PD deficiency and school health. There is an urgent need for better interfaces to be established among the various service providers.

References

1. Chan M. Annual Department Report 1996-1997. Department of Health, Hong Kong Government 1997.

2. Lam TH, Chung SF, Wong CM, Hedley AJ, Betson CL. The Youth Smoking and Health Survey 1994. Hong Kong Council on Smoking and Health. Report No. 1.

3. Yuen KY. Human disease caused by avian influenza A subtype H5N1 virus - an emerging infection. HK J Paediatr (new series) 1998;3:3-4.

4. Yuen KY, Chan PKS, Peiris M, et al. Clinical features and rapid viral diagnosis of human disease associated with avian influenza A H5N1 virus. Lancet 1998;351:467-71.

5. Lau YL, Chan LC, Chan YYA, Ha SY, Yeung CY, Waye JS, Chui DHK. Prevalence and genotypes of α- and β-thalassemia carriers in Hong Kong - Implications for population screening. N Engl J Med 1997;336:1298-301.

6. Lau YL, Karlberg J. Prevalence and risk factors of childhood asthma, rhinitis and eczema in Hong Kong. J Paediatr Child Health 1998;34:47-52.

7. Lau YL, Yung R, Low L, Sung R, Leung CW, Lee WH. Haemophilus influenzae type b infections in Hong Kong. Paediatr Infect Dis J 1998;17(9):S165-9.

8. Lau YL, Low LCK, Yung R, et al. Invasive Haemophilus influenzae type b infections in children hospitalized in Hong Kong, 1986-1990. Acta Pediatr 1995;84:173-6.