Geographical differences in physiques of male youth of age 18-20 years in China.

Three national surveys on the physical status of 18-, 19-, and 20-year-old male candidates for military service were carried out in six geographic regions of China in 1955, 1974, and 2001. Data from these surveys for 72,000 individuals were compared by region, by time, and by age, and estimates of incremental changes by decade were made. Overall, at all time points, males in the north and northeast areas were larger and heavier than males in the southwest. Similarly, the proportion of males in the north and northeast who were overweight was greater than in the other areas. The proportion classified as "thin" was highest in the south, southwest, and northwest, reaching 42.6% in the northwest. When urban and rural areas were compared, the mean value of every measure in every region was higher for urban youth, with all but two comparisons reaching significance (P<0.05). Differences of chest circumference among age groups were significant, as were differences in height, weight, and body mass index for 18-year-olds compared to 20-year-olds. Overall, height increments per decade were greatest for males in the southwest (average of age groups 1.79 cm, 1974 to 2001) and least in the northeast (1.08), indicating some tendency toward convergence over time. Weight increments per decade over the same time were greatest in north China (1.37 kg) and least in the northwest region (0.58 kg).

Geographical differences in blood pressure of male youth aged 17-21 years in China.

Hypertension is one of the most prevalent cardiovascular risk factors in the adult Chinese population. The prevalence distribution of hypertension differs geographically in adults, since hypertension is influenced by environment factors, such as climate, altitude and economic. The aim of the present study was to study the prevalence of hypertension and measure the blood pressure (BP) level, and to compare and observe the geographical distribution of borderline or high BP in Chinese male youth. A cross-sectional survey on constitution and health of Chinese recruit youth was carried out in 2001, using the cluster sampling method. Two to four counties or cantons were selected as survey spots from all the 27 provinces or autonomous regions and four municipalities in China according to its population, geography and economy, except for Hong Kong, Tai Wan and Macao. The total survey spots were 100 counties or cantons. At each survey spot, all the recruit youth aged 17-21 years were surveyed, and data from a total of 81,193 recruits were collected. In the analysis, female youth and male subjects with diseases in heart, kidney, or other organs that could cause high BP were rejected. In all, the analysis sample was 72,895 subjects. Two standardized BP measurements were obtained. According to the P, P centile values of Chinese children and adolescent BP references, and adult's critical hypertension diagnosis standard recommended by the WHO, all the subjects were categorized into seven groups. The relationships between BP and physical indexes, age, heart rate, vital capacity and area were analyzed by using multiple step-wise regression. The prevalence rate of borderline and high BP of male youth in China was 13.3% and 5.0% respectively. There were significant differences in the prevalence rate of relatively high (borderline and high) BP and overall BP among youth from different areas. BP and the prevalence rate of relatively high BP were highest in youth from north China and the northeast areas among the six areas, with a prevalence rate of borderline 25.9% and 14.7%, and the high 10.5% and 5.7% respectively. However, the prevalence rate of relatively high BP of youth from the southwest area was the lowest among the six areas, with a prevalence rate of borderline 5.2% and high 2.3%. The results of multiple step-wise regression analysis showed that height, body mass index, age, heart-rate, vital capacity, economic status were positively correlated with BP, whereas annual mean air temperature, rainfall and altitude were negatively correlated. The results of this study showed that there were significant differences in the prevalence rate of relative high BP in male youth from different areas in China, and that BP was influenced by physical status and living area.