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At least 19 recordsLinked to original sources
PubMedDate not supplied

Normal reference value of hemoglobin of older boys and geographical factors.

UNLABELLED: In order to supply a scientific basis for uniting the normal reference value standard of hemoglobin of Chinese older boys. METHODS: A research is made about the relationship between the normal reference value of 14751 examples of hemoglobin of older boys and five geographical factors in 92 areas in China, which are determined by the hemoglobincyanide method. RESULTS: It is found that the correlation of geographical factors and the normal reference value of hemoglobin of older boys are quite significant (F = 9.68). By using the method of multiple linear regression analysis, one regression equation is inferred: Y = 108.0 + 0.003633X1 + 0.003945X2 + 0.1680X3 - 0.6310X4 + 0.005518X5 +/- 8.3. CONCLUSION: If geographical values are obtained in some areas, the normal reference value of hemoglobin of older boys of this area can be reckoned by using the regression equation. Furthermore, the depending on the geographical factors, China can be divided into six districts: Qingzang, Southwest. Northwest, Southeast, North and Northeast district.

Child↗
PubMed2001

The relationship between the reference value of erythrocyte sedimentation rate and geographical factors.

In order to provide a scientific basis for a unified standard of the reference value of erythrocyte sedimentation rate (ESR) in China, the reference value of healthy people's ESR has been collected. The relationship between the reference value of ESR and geographical factors is examined in this paper. Altitude is the most important factor affecting the reference value of ESR, which decreases with increasing altitude; the relationship is quite significant. The method of stepwise regression analysis was used to deduce two regression equations: Y1 = 12.08 - 0.00222X1 + 0.00114X5 +/- 2.95, Y2 = 18.81 - 0.00323X1 + 0.239X4 +/- 4.70. If the geographical factor value of a particular area in China is known, the reference value of ESR of Chinese people can be calculated by means of the regression equations. Furthermore, the dependence on geographical factors in China can be classified as six districts: Qingzang, Southwest, Northwest, Southeast, North and Northeast.

Adult↗
PubMed2002

Analysis of CCR5Delta32 geographic distribution and its correlation with some climatic and geographic factors.

We studied the possible effects of climatic-geographic factors on the world distribution of the mutant allele for the chemokine receptor gene CCR5, which has a 32-bp deletion (CCR5Delta32) preventing cell invasion by the primary transmitting strain of HIV-1. New data on CCR5 polymorphisms in Russian, Ukrainian, and Moldavian populations are presented. All available data on CCR5Delta32 frequencies in the Old World (number of populations n = 77) were used for construction of a geographical gene map to analyze possible correlations between allele frequencies and eight climatic-geographic parameters. A strong positive correlation was found between the allele frequency and latitude (r = 0.72), a strong negative correlation with annual radiation balance (r = -0.66), and a weaker negative correlation with longitude (r = -0.34). Partial correlations were calculated excluding the influence of latitude. The negative correlation between the allele frequency and annual radiation balance decreased (r = -0.42), but remained large and significant. We propose that the existence of correlations between the cline of CCR5Delta32 frequencies and climatic-geographic parameters provides evidence for a possible effect of either natural environmental factors or large-scale population movements on the distribution of this allele.

Climate↗
PubMed1999

The relationship between normal erythrocyte sedimentation rate of Chinese young people and geographical factors.

In order to provide a scientific basis for the layout of a unified standard of the reference value of Chinese young people's erythrocyte sedimentation rate (ESR), the relationship between the reference values of the Chinese healthy young's ESR and five geographical factors was tested according to the Wintrobe methods. The altitude was found to be the most important factor affecting the reference value of the Chinese young's ESR. The altitude increase correlates with the decrease of the reference value of the young's ESR. The method of stepwise regression analysis was used to deduce two multivariate regression equations. If the geographical index values of a particular area of China are known, the reference value of the young's ESR of this region can be calculated by means of the regression equations. Furthermore, the depending on geographical factors, China can be divided into six districts: Qingzang, Southwest, Northwest, Southeast, North and Northeast District, according to the reference values of the Chinese young's ESR.

Adult↗
PubMed2006

Geographic factors contributing to a high seroprevalence of West Nile virus-specific antibodies in humans following an epidemic.

Sera of 624 blood donors were evaluated to determine seroprevalence of West Nile virus (WNV) antibodies following the 2003 WNV epidemic in Nebraska. Geographic factors contributing to differences in WNV seropositivity were evaluated. The overall prevalence of WNV in Nebraska was higher than reported previously in other U.S. locations (9.5% WNV immunoglobulin G seroprevalence rate), with the highest prevalence identified in the western part of the state (19.7%), followed by the central (13.8%) and the eastern (4.2%) parts. Regions of the state with the highest WNV-positive mosquito rates correlated with the highest human WNV seroprevalence rates. The results showed that both the western and central parts of the state, where mosquito positivity rates were highest, had significantly higher seroprevalence rates than the eastern region. Additional studies are needed to determine whether the high prevalence rates in Nebraska will be reflected in other states and what impact environmental and geographical factors may have on future outbreaks of WNV infection.

Animals↗
PubMedDate not supplied

Discussion on the relationship between normal hematocrit and geographical factors in China.

This paper is written in order to provide a scientific basis for laying out an unified standard of the reference value of hematocrit of Chinese healthy people. It studies the relationship between the reference values of Chinese adults' hematocrit, tested according to the Wintrobe Laws and five geographical factors. It is found that the altitude is the most important factor affecting the reference value of Chinese healthy people's hematocrit. As the altitude gradually increases, the reference value of their hematocrit also increases. By using the method of stepwise regression analysis, two multivariate regression equations are deduced. If the geographical index values in a particular area are known, the reference value of Chinese healthy people's hematocrit in this area can be established by means of the regression equations. Furthermore, according to the dependent relationship of the reference value of Chinese healthy people's hematocrit to geographical factors, China can be divided into six districts: Qingzang, Southwest, Northwest, Southeast, North and Northeast district.

Adolescent↗
PubMed1997

Geographic factors probably modulating alternative pathways in Helicobacter pylori-associated gastroduodenal pathology: a hypothesis.

It is hypothesized that probable geographic factors of nutritional type, nonrelated to development or socioeconomic level, may modulate the conversion of Helicobacter pylori-associated active chronic gastritis from its early stages to chronic atrophic gastritis (CAG). The factors could be diets low in antioxidant vitamins and other micronutrients such as selenium. In regions of the world where these modulating factors are not present, active chronic gastritis tends to stay in its early stages and to predispose individuals to duodenal ulcer. On the contrary, in regions where the modulating factors are present, the frequency of CAG increases markedly. When CAG becomes severe and extensive, hypochlorhydria ensues. Hypochlorhydria decreases the predisposition to duodenal ulcer, while CAG, a precancerous lesion, predisposes individuals to gastric cancer of the intestinal type. The hypothesis could be tested in a multicenter, multiregional study to (1) determine endoscopically and histologically the prevalence rates of duodenal ulcer, gastric ulcer, gastric cancer, and H. pylori-associated CAG in large series of dyspeptic patients and (2) correlate these prevalence rates with blood levels of micronutrients in these patients.

Disease Progression↗
PubMed1996

Hills, ridges, mountains, and roads: geographical factors and access to care in rural Kentucky.

Access to health care remains an important issue facing many individuals. Barriers to health care include financial factors, characteristics of the individuals and of the health care delivery system, as well as geographical factors. Using a telephone survey of Kentucky residents, this study investigated the relationship between the road quality and county elevation and access to health care for individuals in rural and urban areas of the state. Controlling the comparison for known individual characteristics, community characteristics, and medical infrastructure characteristics, this study uncovered that worse road conditions, measured by a road "rideability" index, were associated with longer times to reach medical care. It also found an association between higher county elevations and shorter times to reach medical care.

Catchment Area, Health↗
PubMed2006

Analysis of climatic and geographic factors affecting the presence of chytridiomycosis in Australia.

Chytridiomycosis is an emerging fungal disease that has been implicated in the global decline of amphibian populations. Identifying climatic and geographic factors associated with its presence may be useful in control and prevention measures. Factors such as high altitude, cool temperature, and wet climate have been associated with chytridiomycosis outbreaks. Although some of these factors have been studied in a laboratory setting, there have been few studies in a natural setting. In this investigation, the relationship between altitude, average summer maximum temperature, or the amount of rainfall and the presence or absence of chytridiomycosis are statistically tested using data from 56 study sites in Australia. Currently, in Australia, 48 native species of wild amphibians have been found infected with chytridiomycosis. The 56 sites in the present study, extending along approximately 50% of the coastline of Australia, have been identified as either a chytrid site, where > or = 1 species are infected with chytridiomycosis, or a no-decline site, where none of the species present at the site are experiencing a decline or are known to be infected. The odds-ratio test and two-proportions test applied to this data indicate that the presence of chytridiomycosis in Australia is significantly related to temperature. In particular, the presence of chytridiomycosis is more likely at sites where the average summer maximum temperature is < 30 degrees C. The results of the analyses do not indicate a significant relationship between the presence of chytridiomycosis and altitude or rainfall.

Altitude↗
PubMedDate not supplied

Geographical factors and A&E attendance.

Mike Walsh demonstrates how the technique of multiple regression analysis can be used to clarify the significance of several variables in determining the geographical factors which affect A&E attendance. The results indicate that travelling distance to A&E, social status of the catchment area and the proportion of the population in the 15-29 age group are significant factors in a complex equation.

Catchment Area, Health↗
PubMed1990

[Quantitative epidemiological investigation on social, economic and geographic factors contributing to falciparum malaria in southern Henan province].

A case-control study was conducted at Xinyang prefecture, Henan province in 1988 to investigate social, economic and geographic factors believed to be associated with the occurrence of residual falciparum malaria cases. Data were obtained from 65 residual cases and 195 matched control samples from neighbours, residents in the same village and extravillage. The questionnaire contained a total of 27 relevant items. The results of analysis of conditional logistic multi-regression model with IBM PC/XT microcomputer showed that six important risk factors related to residual falciparum malaria cases, i.e., the type of breeding places, yellow-brown soil, the knowledge of malaria transmission, open-sleep habit, family's malaria history and number of livestock. The epidemiological significance of these findings was discussed briefly.

Animals↗
PubMed1992

[An epidemiological analysis on the geographic factors of esophageal cancer].

The author collects the data of esophageal cancer mortality (1971-1973) of 78 counties in Hubei Province and the data of topography, climate, soil, rock formation and geochemical elements, including 40 suspected factors. The method of linear correlation and multiple stepwise regression are used for the comprehensive analysis of relation between the geographical factors and esophageal cancer. The result is that four factors metamorphic rock, zinc, copper, chromium are suspected factors. It suggests that the four factors will need future study.

China↗
PubMedDate not supplied

Very low birth weight births at non-NICU hospitals: the role of sociodemographic, perinatal, and geographic factors.

PURPOSE: The purpose of this study was to assess the extent of variation in the percentage of very low birth weight (VLBW) infants born at perinatal Level 1 hospitals (no Neonatal Intensive Care Unit [NICU]) across California's nine geographic Perinatal regions. The role of sociodemographic, perinatal, and geographic factors was also assessed. METHODS: Multivariate analysis of California birth certificate files between 1989 and 1993, for 24,094 live-born infants weighing between 500 and 1499 gm, was conducted to identify factors associated with delivery at a Level 1 hospital. Analyses specific for race and ethnicity were also conducted for Hispanic, African American, and white cohorts. RESULTS: In the 5-year study period, 1989 through 1993, 10.5% (24,094) of all live-born VLBW infants were delivered in Level 1 hospitals. Significant variation across regions was evident, ranging from a regional low of 3.1% to a high of 24.3%. After controlling for multiple factors, the odds of delivering at a Level 1 hospital were decreased for African Americans and South East Asians and increased in Hispanic women as compared with white non-Hispanic women. For all women, less then adequate prenatal care, living in a 50% to 75% urban zip code, and living greater then 25 miles from the nearest NICU significantly increased the odds of VLBW delivery at a Level 1 hospital. For Hispanics, teen pregnancy and having two or more prior infant deaths increased the odds, whereas Medi-Cal as the payer source for delivery and two or more pregnancy complications decreased the odds of a Level 1 VLBW delivery. After taking these factors into account, when compared with Los Angeles, the odds of inappropriate delivery site ranged from 0.37 to 2.75 across California's nine geographic perinatal regions. Of this variation, 78% could be accounted for by the percentage of total births that delivered at a region's Level 1 hospitals. CONCLUSION: The overall state average of 10.5% deliveries of VLBW at Level 1 hospitals, although close to the 10% national objective for the year 2000, did not indicate the wide variation seen across California's nine geographic regions. Risk-adjusted regional differences in the likelihood of inappropriate delivery site for the high-risk VLBW infants suggest that reaching the Healthy People 2000 objective will require further strengthening of California's perinatal regional networks, especially in those regions where a high percentage of total births deliver at Level 1 hospitals.

California↗
PubMed1997

[Relationship between reference value (Wintrobe) of Chinese healthy female hematocrit and geographical factors].

To provide a basis for uniting the reference value standard (Wintrobe) of Chinese healthy female hematocrit, a study has been made on the relationship between the reference value of 22135 cases of Chinese female hematocrit and five geographical factors in China's 436 areas, which were determined by the method of Wintrobe. It is found that altitude is the main factor affecting the reference value (Wintrobe) of Chinese healthy female hematocrit. As the altitude increases gradually, the reference value (Wintrobe) of Chinese healthy female hematocrit also increases. For applying the method of mathematical regression analysis, a multivariate regression equation is formulated. In case geographical index values are obtained in an area, the reference value (Wintrobe) of Chinese healthy female heamtocrit for this area can be reckoned using the regression equation. Furthermore, according to the similarity of the reference values (Wintrobe) of Chinese healthy female hematocrit, China can be divided into six regions: Qinghai-Xizang region, southwest region, northwest region, southeast region, north region and northeast region.

Altitude↗
PubMed2003

Antimicrobial susceptibility of lower respiratory tract pathogens in Great Britain and Ireland 1999-2001 related to demographic and geographical factors: the BSAC Respiratory Resistance Surveillance Programme.

OBJECTIVE: The aim of this study was to assess the antimicrobial susceptibility of community-acquired lower respiratory pathogens in Great Britain and Ireland, and investigate its relationship with demographic and geographical factors using multiple logistic regression analysis. METHODS: A total of 1328 isolates of Streptococcus pneumoniae, 1894 Haemophilus influenzae and 845 Moraxella catarrhalis were collected from lower respiratory clinical specimens (primarily sputum) by 20 laboratories in Great Britain (England, Wales and Scotland) and Ireland (Northern Ireland and Eire) between 1999 and 2001. RESULTS: Of 1154 S. pneumoniae from Great Britain, 92-100% were susceptible to beta-lactams (only 0.2% having penicillin MICs > or =2 mg/L), 89% were susceptible to erythromycin, 93% susceptible to tetracycline, and 94-100% intermediate or susceptible to fluoroquinolones. Susceptibility to agents other than fluoroquinolones was less frequent in the 174 isolates from Ireland: beta-lactam susceptibility was 68-99% (3.4% having penicillin MICs > or =2 mg/L), erythromycin susceptibility was 78% and tetracycline susceptibility was 82%. In multivariate analysis, susceptibility in S. pneumoniae was associated with country and patient age, being most common overall in the 20-49 years age group. Of 1894 H. influenzae, 15% produced beta-lactamase and 79-100% were susceptible to beta-lactams other than cefaclor. Ninety-six per cent were intermediate and 1% susceptible to erythromycin, 97% susceptible to tetracycline, and 89% susceptible to trimethoprim. Only one isolate showed resistance to ciprofloxacin. H. influenzae from sputum were more likely to be susceptible than isolates from other sources. Of 845 M. catarrhalis, 92% produced beta-lactamase and 9% were susceptible to ampicillin, >99% were susceptible to co-amoxiclav, cefotaxime, erythromycin and fluoroquinolones. CONCLUSIONS: Clinically relevant demographic factors predictive of susceptibility were country and patient age in S. pneumoniae, and specimen type (sputum/non-sputum) in H. influenzae. Susceptibility to most antimicrobials remains high in Ireland and very high in Great Britain.

Adult↗
PubMed2002

Reference value of presenile human hematocrit and geographical factors.

The aim of this study was to provide a scientific basis for a unified standard of the reference value of healthy presenile human hematocrit in China. We studied the relationship between the reference values of healthy presenile human hematocrit, tested according to Wintrobe's laws, and five geographical factors. It was found that altitude is the most important factor affecting the reference value of the hematocrit. As the altitude gradually increases, the reference value of the hematocrit also increases. The relationship is quite significant. By using the method of stepwise regression analysis, two multivariate regression equations were deduced: Y1 = 39.7 + 0.00328X1 + 0.00169X2 + 0.00117X5 +/- 2.3, Y2 = 38.8 + 0.00275X1 + 0.000578X2 -0.00298X4 +/- 2.2 In these equations, Y1 is the reference value of presenile men's hematocrit (%); Y2 is the reference value of presenile women's hematocrit (%); X1 is altitude (m); X2 is the average annual hours of sunshine (h); X4 is the average annual temperature (degrees C), and X5 is the average annual precipitation (mm). If the geographical index values in a particular area in China are known, the reference value of presenile human hematocrit in this area can be calculated approximately by means of the regression equations.

China↗
PubMedDate not supplied

[Geographical factors in the epidemiology of intoxication with Karwinskia (tullidora) in Mexico].

Consumption of fruits from the genus Karwinskia may cause a flaccid paralysis that can be confused with the Guillan-Barré syndrome or poliomyelitis. Paralysis resulting from consumption of such fruit has emerged as a public health problem in certain regions of Mexico. The purpose of this study was to investigate geographical factors associated with this intoxication in the 72 cases reported in Mexico from 1990 to 1994. Location of cases coincides with the distribution of the 11 reported species of Karwinskia in the country. The majority of reported cases were related to the consumption of K. humboldtiana, with a smaller number involving K. mollis, K. parvifolia, K. johnstonii, and K. rzedowskii. Most cases were located in regions with dry climates (79.2%), arid vegetation (41. 7%), and altitudes under 1,000 meters above sea level (54.1%). The study establishes three different risk areas: the Balsas river region in the southwestern central part of the country; the arid northern area; and the arid and dry central area. Cases were from rural communities with low levels of schooling and poor socioeconomic conditions.

Child↗
PubMed1990

Payment to health maintenance organizations and the geographic factor.

The adjusted average per capita cost (AAPCC) payment system for Medicare risk-based plans uses a county level geographic adjustment factor to account for differences in beneficiary costs across areas. The implications of abandoning the county unit as the basis of the geographic area are examined and the merging of counties to match the geographic definition used in the prospective payment system are considered. Year-to-year variation in a county AAPCC is inversely associated with county population size and, based on year-to-year AAPCC variation, 86 percent of all counties are too small to be used for the geographic adjustment.

Aged↗