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Biomedical subjects

T H Lam

Publications and source records attributed to T H Lam.

At least 127 records · Page 7Linked to original sources
PubMed1995

Oesophageal cancer in never-smokers and never-drinkers.

Alcohol, tobacco and diet are the most important determinants of oesophageal cancer. Previous studies which examined smoking in non-drinkers and drinking in non-smokers did not report the main effects of dietary factors or the smoking and drinking effects adjusted for dietary factors. Data from a hospital-based case-control study in Hong Kong Chinese were used to examine the effects of dietary variables as well as tobacco and alcohol in never-drinkers and never-smokers. Among the 400 cases, there were 68 never-smokers and 53 never-drinkers; 540 were never-smokers and 407 were never-drinkers among 1598 controls. In never-smokers, alcohol drinking was strongly associated with risk. Use of green leafy vegetables and citrus fruits was protective. Among never-drinkers, smokers had increased risk, but the protective effect of vegetables and fruits did not reach statistical significance. In never-smokers and in never-drinkers alike, frequent consumption of pickled vegetables and being born in Teochew or Hokkien were associated with increased risks. This study provides further support for the independent effects of alcohol, tobacco and diet in oesophageal cancer.

Aged↗
PubMed1995

Stress and vulnerability in medical students.

One hundred and forty Hong Kong Chinese students were surveyed early in the second year of their medical education (year 2), and compared with 138 students surveyed prior to beginning their first year of medical school and with 74 non-medical university students in their second year. In year 2 students, distress as reflected in their scores on anxiety and depression self-report scales was high, and these students reported greater utilization of health professional services as compared with the other two groups. In year 2 students, concerns related to the medical school environment and curriculum, and whether one has the endurance and ability to be successful were significant correlates with depression and anxiety. Loss of opportunity to maintain social and recreational sources of gratification correlated with anxiety. There was no difference between the sexes with regard to the development of anxiety and depression symptoms. Academically less successful students reported somewhat higher levels of depressive ideation and symptomatology. Trait anxiety correlated with the development of distress, while optimism protected against the development of distress. Active coping styles and positive reinterpretation as a coping strategy correlated negatively with distress, while wishful thinking correlated positively with distress. These findings emphasize the need for greater attention to the psychological well-being of doctors-in-training, in Hong Kong as in the Western world. These findings should be further explored in longitudinal studies, and may be helpful in designing intervention and support programmes for vulnerable students.

Adult↗
PubMed1995

Byssinosis in Guangzhou, China.

OBJECTIVES: To study the prevalence of byssinosis and other respiratory abnormalities in workers exposed to cotton dust in Guangzhou in two factories that processed purely cotton. METHODS: All the 1320 workers exposed were included. The controls were 1306 workers with no history of occupational dust exposure. Total dust and inhalable dust were measured by Chinese total dust sampler and American vertical elutriator respectively. A World Health Organisation questionnaire was used. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured by a Vitalograph spirometer. RESULTS: The median inhalable dust concentrations ranged from 0.41 to 1.51 mg/m3 and median total dust concentrations from 3.04 to 12.32 mg/m3. The prevalence of respiratory abnormalities in the cotton workers were (a) typical Monday symptoms 9.0%; (b) FEV1 fall by > or = 5% after a shift 16.8%; (c) FEV1 fall by > or = 10% after a shift 4.2%; (d) FEV1 < 80% predicted 6.1%; (e) FEV1/FVC < 75% 4.0%; (f) cough or phlegm 18.2%; (g) chronic bronchitis 10.9%; and (h) byssinosis, defined by (a) plus (b) 1.7%. With the exception of (d), most of the prevalences increased with increasing age, duration of exposure, and cumulative inhalable dust exposure. No increasing trends of respiratory abnormalities were found for current total dust, inhalable dust, and cumulative total dust concentrations. Compared with controls, after adjustment for sex and smoking, with the exception of (d), all the pooled relative risks of respiratory abnormalities were raised for cotton exposure. CONCLUSION: It is concluded that cumulative inhalable cotton is likely to be the cause of byssinotic symptoms, acute lung function decrements, cough, or phlegm, and chronic bronchitis.

Adolescent↗
PubMed1995

Factors influencing smoking behavior in Hong Kong primary schoolchildren: targets for prevention.

The uptake of smoking by children and factors influencing such behavior, although well documented in the West, have not been studied in the Asia-Pacific region. A cross-sectional survey was carried out on 3,521 children, aged 8-11 years living in two districts of Hong Kong. Knowledge, attitude and behavior related to smoking and sociodemographic data were obtained from questionnaires completed by parents and children. Eleven percent of boys and 5 percent of girls were ever-smokers, 5 percent of all eight-year-olds and 21 percent of 11-year-olds. Believing that parents will not interfere with their smoking (adjusted odds ratio 5.52; 95% confidence interval 2.72, 11.18), living with family members who smoke (1.72; 1.33, 2.23), and having a positive attitude to smoking (4.13; 1.43, 11.98) were factors predictive of ever-smokers. Experimentation with smoking is a major health risk for primary school children in Hong Kong and indicates failure of current smoking prevention programs. Effective culture-specific programs to counteract risk factors and with continuing evaluation are urgently needed; they should be based on information from appropriately-designed epidemiological studies.

Child↗
PubMed1994

Passive smoking at work as a risk factor for coronary heart disease in Chinese women who have never smoked.

OBJECTIVE: To study whether passive smoking at work is a risk factor for coronary heart disease. DESIGN: Case-control study. SETTING: Xi'an, China. SUBJECTS: 59 patients with coronary heart disease and 126 controls, all Chinese women with full time jobs, who had never smoked cigarettes. RESULTS: The crude odds ratio for passive smoking from husband was 2.12 (95% confidence interval 1.06 to 4.25) and at work was 2.45 (1.23 to 4.88). The final logistic regression model, with passive smoking from husband and at work as the base, included age, history of hypertension, type A personality, and total cholesterol and high density lipoprotein cholesterol concentrations; the adjusted odds ratios for passive smoking from husband and at work were 1.24 (0.56 to 2.72) and 1.85 (0.86 to 4.00) respectively. For passive smoking at work, statistically significant linear trends of increasing risks (for both crude and adjusted odds ratios) with increasing exposures (amount exposed daily, number of smokers, number of hours exposed daily, and cumulative exposure) were observed. When these exposure variables were analysed as continuous variables, the crude and adjusted odds ratios were also significant. CONCLUSION: Passive smoking at work is a risk factor for coronary heart disease. Urgent public health measures are needed to reduce smoking and to protect non-smokers from passive smoking in China.

Adult↗
PubMed1994

Bronchial responsiveness in children exposed to atmospheric pollution in Hong Kong.

Bronchial responsiveness was studied by histamine challenge in 423 school children with mean (SEM) age of 10.85 (0.05) years living in two districts of Hong Kong with contrasting levels of air pollution. Differences between districts of residence were observed, with a higher prevalence of bronchial hyperreactivity (BHR) in children living in the more polluted district (chi 2 = 7.74, df = 3, p = 0.052). Bronchial hyperreactivity was defined as a 20 percent or greater drop in FEV1. The district effect remained after exclusion of children with a history of wheeze and those diagnosed asthmatic for prevalence of BHR (chi 2 = 8.93, df = 3, p = 0.030) and for degree of bronchial reactivity (BR) after adjustment for other socioeconomic factors and smoking in the home (z = 1.97, p = 0.049). Bronchial reactivity was defined as the percentage drop in FEV1 per cumulative histamine dose from postsaline to end dose. The results demonstrate that studies on bronchial responsiveness can be used to assess the effects of air quality on the respiratory health of children and will be employed to measure the impact of new air quality control measures in Hong Kong.

Air Pollution↗
PubMed1993

Sensitive high-performance liquid chromatographic assay for the determination of chlorhexidine in saliva.

A high-performance liquid chromatographic assay was developed to determine salivary chlorhexidine concentration. Saliva sample (200 microliters) was extracted into methylene chloride. Chromatographic separation was achieved with a C18 column using a mobile phase of acetonitrile-0.05 M sodium acetate and 0.005 M heptanesulfonic acid (40:60, v/v). The standard curve was linear from 0.051 to 20.48 micrograms/ml (r2 > or = 0.997). Intra-day and inter-day coefficients of variation were < 5.5 and < or = 9%, respectively. The assay is rapid, sensitive, simple, and successfully used for quantitating salivary chlorhexidine content released from a chlorhexidine-impregnated resin worn by patients.

Chlorhexidine↗
PubMed1992

Pickled vegetables in the aetiology of oesophageal cancer in Hong Kong Chinese.

Oesophageal cancer is common in Chinese populations, but individual-based epidemiological studies have provided little explanation. A case control study with 400 cases and 1598 controls (800 hospital and 798 general practice) was conducted among Hong Kong Chinese. In multivariate analyses, statistically significant effects on risk were detected for several potentially preventable exposures with high attributable risks (ARs). These included preference for consuming drinks or soups at high temperature (AR = 14%), infrequent consumption of green leafy vegetables (AR = 15%) and citrus fruits (AR = 26%), ingestion of pickled vegetables (AR = 29%), tobacco smoking (AR = 44%), and alcohol drinking (AR = 48%). On the assumption of multiplicative risk, the combined AR due to these exposures was 89%. This is the first case control study to show an association between pickled vegetable consumption and oesophageal cancer risk. The finding considerably strengthens the evidence for carcinogenicity of N-nitroso compounds in man and helps to explain the very high risk among Chinese.

Aged↗
PubMed1992

Dysbaric osteonecrosis in a compressed air tunnelling project in Hong Kong.

In the largest compressed air tunnelling project using the Blackpool Decompression Tables in Hong Kong, 912 men had radiological examination of major joints and 12 definite and 30 suspected cases of dysbaric osteonecrosis were detected by the compressed air physician. Distribution of the lesions was symmetrical and 43.1 per cent were juxta-articular. All the cases were asymptomatic. The infrequent occurrence of osteonecrosis in Hong Kong in general and in this project in particular suggests that the Blackpool Tables were relatively effective in preventing the disease. Definite and suspected cases were pooled together for the study of risk factors for osteonecrosis. Logistic regression analysis showed that the number of bends ever experienced, number of hours worked in the present contract, age and obesity were important independent risk factors. Because of the impossibility of a suitably long follow-up for all workers, the prevalence of osteonecrosis may be under-reported in Hong Kong.

Adult↗
PubMed1991

Studies on the respiratory health of primary school children in urban communities of Hong Kong.

The first stage of a 2-year survey of respiratory morbidity in primary school children was conducted in two districts of Hong Kong in April/May 1989. One group (2009) of children was from Kwai Tsing District, which had high levels of exhaust emission from factories. The other group (1837) was from Southern District where atmospheric pollution was considered to be relatively low. After adjustment for gender, age, socioeconomic factors, child smoking and exposure to parental smoking, the prevalence ratios of sore throat, evening cough, cough for more than 3 months, morning phlegm and wheezing were found to be significantly higher in Kwai Tsing. The difference between the districts is likely to be related to the environmental air quality. The study, which is continuing, will provide the basis for an evaluation of the impact of new low sulphur fuel regulations introduced in July 1990.

Acute Disease↗
PubMed1991

Contact dermatitis due to topical treatment with garlic in Hong Kong.

Contact dermatitis due to garlic is usually due to handling of garlic for cooking. Among the Chinese, garlic is also used as a form of topical medicament. 8 patients developed contact dermatitis after rubbing the cut end of a fresh garlic bulb onto the skin to treat fungal and other infections at the groin, neck, lower limb, hand or face. The distribution and morphology of the lesions were different from the classical form as described in the literature. Repeated open application tests with fresh garlic were all positive and patch tests with garlic extract were all negative. 5 controls tested by repeated open application with fresh garlic juice were also positive and patch tests in 10 controls with garlic extract were also negative. The results confirmed that the contact dermatitis was due to irritation. The patients were treated successfully with topical fluorinated steroid. For prevention, the practice of direct application of fresh garlic onto the skin for treating infections should be discouraged.

Administration, Cutaneous↗
PubMed1990

Smoking among young doctors in Hong Kong: a message to medical educators.

A survey was conducted using a self-administered questionnaire to examine the smoking habits, attitudes and practices of 151 doctors in their pre-registration year. The response rate was 88%. Over 80% of the respondents had never smoked. Less than 7% of the men smoked daily and none of the women smoked. Despite a very low smoking rate among the respondents, there were shortcomings in attitudes and practices. The study demonstrated that even in a place like Hong Kong, where the social climate on smoking is already changing in a healthy direction, significant deficiencies in our graduates can still arise if teaching on smoking and its control is undertaken in an uncoordinated manner. We argue that a specific course on the important aspects of smoking and health should be introduced into all undergraduate curricula. This is of special importance in countries where smoking is one the increase and where governmental actions on smoking control are inadequate in comparison with the marketing efforts of powerful multinational tobacco companies. Considering the magnitude of smoking as a global health problem, it is the very least that medical educators should do in combating this pandemic.

Adult↗
PubMed1990

Risk factors of suicide among schizophrenics.

This case control study included 74 Chinese schizophrenics (DSM-III criteria) who died of suicide and 74 age- and sex-matched nonsuicide schizophrenics. Sociodemographic variables were unrelated with suicide. Associations were found between suicide and severity of illness (more frequent admissions, higher dose of medication and earlier appointments), history of major depressive episodes and suicidal attempts, last admission for reasons other than schizophrenic symptoms alone, and suicidal ideas on mental state examination. The last 2 factors, together with the maintenance dose of medication, were identified as the most important risk factors by logistic regression analysis.

Adult↗