我国南北血压差异及其膳食因素的作用.ppt

我国南北血压差异及其膳食 因素的作用 营养与血压的国际合作研究 (INTERMAP Study),中国医学科学院 心血管病研究所 阜外心血管病医院 赵连成 周北凡 武阳丰,INTERnational collaborative study on MAcronutrients and Blood pressure (Financially supported by NHLBI),INTERMAP 研究简介,INTERMAP 研究背景,一般人群中，人群血压水平从中年开始明显增加； 而在一些特殊人群中，人群血压水平没有随年龄增加或增加不明显； 移民流行病学研究提示，人群血压水平以及血压随年龄增加的现象与生活方式有关； 已有的研究提示生活方式如膳食因素(BMI、钠、钾、饮酒等）因素与血压有关； 缺乏高质量的、大规模、不同人群背景的研究；,INTERMAP 主要研究目的,探讨多种膳食营养因素与血压的关系。,INTERMAP研究特点,横断面研究； 4个国家，17个研究人群； 中年人群，4059岁，共4680人； 高质量的研究方法，包括统一、高质量的膳食调查方法； 具有可比性的食物成分表评估营养素的摄入量。,INTERMAP Field Centers: China 营养与血压关系的国际合作研究,.,.,.,Beijing Shanxi Guangxi,INTERMAP Field Centers: Japan,Sapporo,.,.,.,.,Toyama,Aito Town,Wakayama,INTERMAP Centers: United Kingdom,.,.,.,Belfast Birmingham London (Coordinating Center),Minneapolis Chicago,INTERMAP Field Centers: United States,Pittsburgh,Baltimore,Jackson,Houston,Corpus Christi,Honolulu,.,.,.,.,.,.,.,.,Background,Blood pressure (BP) and prevalence of high BP are greater for northern than for southern Chinese. Although a few studies suggest that heavier body mass and higher salt intake in the north are related to these BP differences, these unfavorable characteristics only partially explained the north-south BP differences.,Purpose,To evaluate multiple dietary factors in determining North-South BP differences in China.,Study Population,There are three Chinese rural samples, two from the North (Pinggu Conuty, Beijing, and Yu County, Shanxi ) and one from the South (Wuming County, Guangxi); Population-based sample; 260 persons (1 per family) was randomly selected from each target population, stratified by gender 10-year age group.,Measurements,Field work was conducted in 1997-1998. Each participant attended the local center on four occasions two pairs of consecutive days about 3-6 weeks apart. Blood pressure was measured twice at each visit with a random zero sphygmomanometer. Height and weight without shoes or heavy clothes were measured at the first and third visits.,Dietary Measurements,Dietary data were collected at each of the four visits by standardized 24-hour dietary recalls. Nutrients were calculated with use of an extensive database, derived from the Chinese national food table and enhanced by the Nutrition Coordinating Center (NCC), University of Minnesota. Two timed 24-hour urine specimens were collected. Urine aliquots were stored frozen at -20oC and then air-freighted frozen to the Central Laboratory where urinary Na, K, and other indices were measured.,Quality Control,INTERMAP protocol, Manuals of Operation; China addendum to the Nutrition Manual (including Chinese Coding Manual); All stuff trained and certificated; Central training and certification for all dietary interviewers; Dry run; Standard food models, calibrated utensils, scales, pictures,etc.;,Quality Control- continued,Collected information from cooks; Monitoring of interviewers during field work; Tape recording of all interviews, review of randomly selected tape and timely feedback to the interviewers; Dietary data coded on survey day; Daily local recording of 10% of recalls by Site Nutritionist and feedback; Recording of 10% of randomly selected recalls by Country Nutritionist and feedback to local centers timely.,Statistical Methods,Measurements for each individual were averaged across visits. Two northern samples (Beijing and Shanxi) were combined as a “North” sample set (Since BP levels as well as most dietary and non-dietary variables were similar for them), and Guangxi sample was designated the “South” sample. Multiple linear regression models were used to examine relations of dietary factors to North-South differences in SBP/DBP.,Average SBP by Sample (Men and Women Combined, N=839),Compared to the South (Guangxi), all P-values0.001),Compared to the South (Guangxi), all P-values0.001),Average DBP by Sample (Men and Women Combined, N=839),Mean or Prevalence of Selected Variables by Sample (Men and Women Combined, N=839),* P0.001 for North vs South (t test or 2 test),Mean Nutrient Intake by Sample,* P0.001 for North vs South (t test or 2 test),Mean Nutrient Intake by Sample - continued,* P0.001 for North vs South (t test or 2 test),Relations of Variables Considered Singly to North-South SBP/DBP Differences,* Coefficient for difference in BP (mm Hg ) between North and South. Percent reduction in site-BP coefficient compared to Model 1.,* Coefficient for difference in BP (mm Hg between North and South. Percent reduction in site-BP coefficient compared to Model 1.,Relations of Variables Considered Singly to North-South SBP/DBP Differences - continued,* Coefficient for SBP difference (mm Hg) between the North and the South. Percent reduction in site (North-South)-SBP coefficient compared to Model 1 (without BMI). Percent reduction in site (North-South)-SBP coefficient compared to Model 2 (without BMI). § P- value0.05,Relations of Combinations of Dietary Variables to North-South SBP Differences,* Coefficient for DBP difference (mm Hg) between the North and the South. Percent reduction in site (North-South)-DBP coefficient compared to Model 1 (without BMI). Percent reduction in site (North-South)-DBP coefficient compared to Model 2 (without BMI). § P- value0.05,Relations of Combinations of Dietary Variables to North-South DBP Differences,Summary,Northern Chinese had significantly higher SBP/DBP (7.4/6.9 mm Hg higher) than Southerners. In general, Southerners had putatively healthier lifestyles than Northerners, e.g., lower BMI and sodium intake, and higher physical activity and micronutrient intake (vitamin A, vitamin C, calcium, magnesium, phosphorus). Combinations of several dietary variables especially Na, K, phosphorus or magnesium, and BMI reduced North-South BP differences to non-significant levels.,Conclusion,Multiple dietary factors account importantly for North-South BP differences in China. In addition to the known importance of maintaining an optimal body weight and lower salt intake, higher intake of certain micronutrients may be valuable measures to improve population BP levels.,