Body mass index profile in Hong Kong Chinese adults

INTRODUCTION

Obesity has now become an epidemic with increasing prevalence in most parts of the world. However, information on the problem of obesity in Asians is limited.

SUBJECTS AND METHODS

From April 1996 to August 1997, 17,121 Chinese adult subjects from the community of Hong Kong presented themselves voluntarily at the United Christian Nethersole Community Health Service Centers for primary health care check-up. Demographic data including height and weight were documented. Their body mass indexes (BMI) were measured. The prevalence rates of overweight and obese subjects were calculated according to the 1995 World Health Organization criteria.

RESULTS

There were 4781 (27.9%) men and 12,340 (72.1%) women. The mean age (+/- SD) was 51.3 +/- 16.0 years (range 20 to 96 years, median 49.8 years). Of the 17,121 subjects, 4939 (28.85%) were overweight and 656 (3.83%) were obese. Based on the 1997 Hong Kong Census statistics of the overall Hong Kong population data, the age-standardised prevalence rates of overweight and obese subjects were 30.52% and 3.19% in men and 22.14% and 3.35% in women, respectively. Of the 10,937 subjects of working age (20 to 65 years), the prevalence rates of overweight and obese subjects were 28.98% and 3.55%, respectively. Of the 6648 subjects aged > or = 60 years, the prevalence rates of overweight and obese subjects were 36.31% and 4.81%, respectively.

CONCLUSIONS

In Hong Kong, the age-standardised prevalence rate of overweight and obese subjects were 30.5% and 3.2% in men and 22.1% and 3.4% in women, respectively. This information provides some useful estimations of the extent of an important public health problem, obesity, in Hong Kong.

Lower BMI cut-off value to define obesity in Hong Kong Chinese: an analysis based on body fat assessment by bioelectrical impedance

There is increasing evidence suggesting that the cut-off values for defining obesity used in the Western countries cannot be readily applied to Asians, who often have smaller body frames than Caucasians. We examined the BMI and body fat (BF) as measured by bioelectrical impedance in 5153 Hong Kong Chinese subjects. We aimed to assess the optimal BMI reflecting obesity as defined by abnormal BF in Hong Kong Chinese. Receiver operating characteristic curve (ROC) analysis was used to assess the optimal BMI predicting BF at different levels. The mean age and SD of the 5153 subjects (3734 women and 1419 men) was 51.5 (SD 16.3) years (range: 18.0-89.5 years, median: 50.7 years). Age-adjusted partial correlation (r) between BMI and BF in women and men were 0.899 (P < 0.001) and 0.818 (P < 0.001) respectively. Using ROC analysis, the BMI corresponding to the conventional upper limit of normal BF was 22.5-23.1 kg/m(2), and the BMI corresponding to the 90 percentiles of BF was 25.4-26.1 kg/m(2). Despite similar body fat contents, the BMI cut-off value used to define obesity in Hong Kong Chinese should be lower as compared to Caucasians. We suggest a BMI of 23 kg/m(2) and 26 kg/m(2) as the cut-off values to define overweight and obesity respectively in Hong Kong Chinese.

Metastatic tumour of the tunica vaginalis testis from carcinoma of the stomach

A 50-year-old man with advanced inoperable gastric adenocarcinoma and diffuse peritoneal metastasis received six cycles of palliative chemotherapy and responded clinically with weight gain. Two months after the completion of chemotherapy, however, he developed a left hydrocele. Aspiration yielded 70 ml of yellowish hydrocele fluid, which contained metastatic adenocarcinoma cells, consistent with a gastric primary tumour. A diagnosis of malignant hydrocele was made. Two weeks later, he developed a painful recurrent left hydrocele with increasing pain and swelling. Left orchidectomy was performed. Tiny white mural nodules measuring 1 mm in size were noted on the tunica vaginalis. No focal lesion was noted in the testis. On microscopic examination, the tunica vaginalis showed reactive mesothelial hyperplasia and extensive lymphatic permeation by poorly differentiated adenocarcinoma, consistent with a gastric primary tumour.

Quadruple primary neoplasms in a 27-year-old woman

A27-year-old woman was referred to our department on 3 February 1998 with a diagnosis of malignant melanoma associated with cystic teratoma of ovary. She had had a laparotomy and bilateral salphingo-oophorectomy on 5 January 1998. Pathology revealed tumour involvement of left ovary, left parametrium and malignant ascites, the right ovary showed polycystic disease, the uterus showed simple hyperplasia of endothelium, the omentum had no tumour and subdiaphragmatic scrapping was negative. On histological examination of the tumour, the cystic portion was basically a cystic teratoma with presence of skin, glial and bony tissue, the solid portion consisted of sheets of undifferentiated tumour cells, which on immunohistochemical staining shown strong positivity to HMB 45 and S-100. Ultrastructual examination confirmed melanocytic differentiation.

Her chest X-ray was clear. Computed tomography of abdomen and pelvis suggested bilobar liver metastasis and significant para-aortic lymphadenopathy. The alpha-fetoprotein (αFP) and beta-human chorionic gonadotrophin (β-hCG) were within normal limits. The diagnosis was a malignant melanoma arising in cystic teratoma of ovary, stage IV disease.

Her past medical history included multiple primary neoplasms. She had right thigh cutaneous histiocytoma at the age of 20 years, with complete excision performed. She developed poorly differentiated invasive ductal carcinoma of left breast (stage pT2N0M0) at the age of 21 years and had a left mastectomy and left axillary clearance; no postoperative adjuvant treatment was given. She also recently had multiple thyroid nodules which shown atypical cells, suggestive of a follicular neoplasm, and total thyroidectomy was contemplated.

Evaluation of her family revealed a strong family history of malignancy. Her twin sister died of a primary brain tumour at the age of 8 years. Her father died of lung cancer at the age of 45 years. Her paternal grandfather died of lung cancer in his 60s. Her paternal grandmother died of primary liver cancer in her 60s. One of her paternal half-uncles (mutual grandfather, different grandmothers) died of a primary brain tumour in his 50s while another died of lung cancer in his 70s. There was no positive family history of malignancy on her maternal side (Figure 1).

She was treated with combination chemotherapy using cisplatin (75 mg/m2) and cyclophosphamide (750 mg/m2). However, she deteriorated rapidly after the first cycle of chemotherapy and died on 16 March 1998.

Combined use of a fasting plasma glucose concentration and HbA1c or fructosamine predicts the likelihood of having diabetes in high-risk subjects

OBJECTIVE

To assess the validity of using fasting plasma glucose (FPG) concentrations in conjunction with HbA1c or fructosamine for the screening of diabetes in high-risk individuals.

RESEARCH DESIGN AND METHODS

In this study 2,877 Hong Kong Chinese (565 [19.6%] men; 2,312 [80.4%] women) with various risk factors for glucose intolerance underwent a 75-g oral glucose tolerance test (OGTT) for screening of diabetes. The risk factors included a family history positive for diabetes, a history of gestational diabetes or impaired glucose tolerance, and obesity.

RESULTS

Using World Health Organization (WHO) criteria, 1,593 (55.4%) had normal glucose tolerance, 657 (22.8%) had impaired glucose tolerance, and 627 (21.8%) had diabetes. When the 1997 American Diabetes Association (ADA) criteria were applied, 394 (13.7%) had diabetes with an FPG > or = 7.0 mmol/l. Using multiple receiver operating characteristic curve analysis, the paired values of an FPG of 5.6 mmol/l and a HbA1c of 5.5% gave an optimal sensitivity of 83.8% and specificity of 83.6% to predict a 2-h plasma glucose (PG) > or = 11.1 mmol/l. Likewise, the paired values of an FPG of 5.4 mmol/l and a fructosamine level of 235 mumol/l (n = 2,408) gave an optimal sensitivity of 81.5% and specificity of 83.2%. An FPG > or = 5.6 mmol/l and an HbA1c > or = 5.5% was 5.4-fold more likely to occur in diabetic subjects (based on the WHO criteria) compared with nondiabetic subjects. For paired parameters less than these values, the likelihood ratio of this occurring in diabetic subjects was only 0.11. Similarly, an FPG > or = 5.4 mmol/l and a fructosamine > or = 235 mumol/l was fivefold more likely to occur in diabetic subjects than in nondiabetic subjects, with both parameters less than these values having a likelihood ratio of 0.04. Using these paired values as initial screening tests, only subjects who had an FPG > or = 5.6 mmol/l and < 7.8 mmol/l and an HbA1c > or = 5.5% (n = 642) required an OGTT to confirm diabetes, thereby saving 77.7% [(2,877-642)/2,877] of the OGTTs performed. Similarly, only subjects who had an FPG > or = 5.4 mmol/l and < 7.8 mmol/l and a fructosamine > or = 235 mumol/l (n = 526) required OGTT to confirm diabetes, meaning that 78.2% [(2,408-526)/2,408] of the OGTTs could have been saved. Based on the 1997 ADA criterion of an FPG cutoff value of 7.0 mmol/l, the corresponding numbers of OGTTs to be saved were 82.6% and 85.5%, respectively.

CONCLUSIONS

The paired values of FPG and HbA1c or FPG and fructosamine helped to identify potentially diabetic subjects, the diagnosis of which could be further confirmed by the 75-g OGTT. Using this approach approximately 80% of OGTTs could have been saved, depending on the diagnostic cutoff value of FPG.

Simple anthropometric indexes and cardiovascular risk factors in Chinese

OBJECTIVE

Obesity is a major public health problem due to its associations with multiple cardiovascular risk factors. Although there are sophisticated methods, such as imaging, to document total body fat and its distributions, anthropometric measurements remain important in clinical practice. We examined the relationships between cardiovascular risk factors and the three commonest anthropometric measurements for obesity, body mass index (BMI), waist-hip ratio (WHR) and waist circumference (WC), in Hong Kong Chinese subjects.

DESIGN AND SETTING

The data are obtained from a prevalence survey for glucose intolerance and lipid abnormality in a representative Hong Kong Chinese working population. All employees from a public utility company and a regional hospital were invited to participate.

SUBJECTS

There were 1513 subjects (910 men and 603 women, mean age +/- s.e.m.: 37.5 +/- 0.2 y). All of them had no significant past medical history.

MEASUREMENTS

BMI, WHR and WC of the 1513 subjects were assessed for their relationships with various cardiovascular risk factors. These include blood pressure, fasting and 2 h plasma glucose and insulin, glycated haemoglobin, total cholesterol, triglyceride, high density and low density lipoprotein cholesterol, and urine albumin concentration.

RESULTS

After age adjustment, all three anthropometric indexes were significantly correlated with the major cardiovascular risk factors in both men and women. When BMI, WHR and WC were analysed according to quartiles, there was a significant trend for blood pressure, plasma triglyceride, fasting and 2 h plasma glucose and insulin to increase, and high density lipoprotein cholesterol to decrease, with increasing obesity after adjustment for age and smoking. Using stepwise regression analysis with the three indexes as independent variables, most of the variance in blood pressure, plasma lipid, insulin, glucose and urinary albumin concentration were explained either by WC or WHR. In women, BMI was the main explanatory variable for reduced high density lipoprotein cholesterol.

CONCLUSIONS

In Hong Kong Chinese, BMI, WHR and WC provide important information in assessing cardiovascular risks. In men, central adiposity as reflected by WC and to some extent, WHR, explained most of the variance in blood pressure, plasma glucose, lipid, insulin and albuminuria. In women, all three indexes reflecting general and central obesity contribute to the variance in these risk factors.

The effect of age on cardiovascular risk factors in Chinese women

Chinese women traditionally have a low incidence of coronary heart disease. However, information on cardiovascular risk factors in this population are relatively scarce. We examined these risk factors in 601 Hong Kong Chinese women (age+/-SEM, 38.5+/-0.4 years; range, 18-66 years) stratified into four age groups (group 1, < or =30 years; group 2, 31-40 years; group 3, 41-50 years; group 4, > or =51 years). Increasing age in Chinese women was associated with increased body mass index, waist-to-hip ratio, systolic and diastolic blood pressure, fasting plasma total cholesterol, triglyceride, low-density lipoprotein, apolipoprotein B, fasting and 2-h plasma glucose, glycated haemoglobin, fasting plasma insulin and urate concentrations. After adjustment for body mass index, waist-to-hip ratio and smoking, all these age-related associations remained statistically significant except for fasting plasma insulin concentration. There was a progressive increase with age in the prevalence of glucose intolerance, hypertension, dyslipidaemia and obesity. These prevalence rates further increased in subjects aged 51 years (the mean menopausal age in Asian women) or above. These findings suggest that age had an important and independent effect on cardiovascular risk in Chinese women and that, as in Caucasians, the onset of menopause might further increase this risk.