Serum cholesterol changes from 1983-1984 to 1993-1994 in the People's Republic of China.

BACKGROUND AND AIM: Increasing cardiovascular disease (CVD) mortality in the People's Republic of China (PRC) led to the 1981 establishment of the PRC-USA Study of Cardiovascular and Cardiopulmonary Epidemiology which, among other objectives, is concerned with the correlates of CVD morbidity and mortality in Chinese populations among other objectives. This report describes changes in total cholesterol (TC) levels in four PRC populations from 1983 to 1993 and identifies factors related to the changes. METHODS AND RESULTS: Population screenings carried out in 1983-1984, 1987-1988 and 1993-1994 involved the collection of demographic data, specimens (including blood), medical history and physical examination data. The data from cohort and independent samples were used to assess TC changes in urban and rural men and women over the decade, with and without adjustment for age and body mass index (BMI) changes. For Guangzhou men and women, the cohort analyses (aged 35-54 at baseline) showed increases in TC of 10-20 mg/dL after adjustment for age and changes in BMI; the independent sample analyses (aged 35-44) also showed higher average TC levels in 1993-1994 than in 1983-1984. For the Beijing cohorts, the results showed decreases in TC during the decade in men, an increase in TC in urban women and no change in rural women; the independent sample analyses indicated declines in TC for Beijing men and women. Possible reasons for the Guangzhou TC increases are economic growth, and dietary and BMI changes. The mean age-adjusted BMI significantly increased (5-10%) over the 10-year period in all of the studied groups. CONCLUSIONS: TC increased 10-20 mg/dL in Guangzhou men and women, probably as a result of socioeconomic development during the decade. The inconsistent patterns of TC changes in Beijing require further study.

Blood pressure and heart rate response during exercise in men and women in the USA and Russia lipid research clinics prevalence study.

Examination of blood pressure (BP) and heart rate (HR) measurements at rest and during exercise in samples of USA and Russian middle-aged men and women show significant differences between countries for both genders. Russian men had higher resting systolic blood pressure (SBP) than USA men but lower SBP at both stages of exercise. Russian women had significantly higher resting SBP than USA women at rest and also during exercise. Russian men and women had significantly lower HR at rest and during exercise than USA men and women. Differences between countries were also noted for mean body weight, height, lipid levels, percentages of smokers and several other variables, and it was postulated that differences in these factors might be responsible in part for differences in SBP and HR during exercise. After adjustment for these variables, differences in SBP during exercise between USA and Russian men remained, but differences between USA and Russian women disappeared. For both genders, differences in HR during exercise remained after adjustment. Mortality analyses in USA and Russian men indicated that stage 2 SBP response during exercise was generally not a significant mortality risk factor after adjustment for age, BMI, TC, smoking and resting SBP. In a similar model, stage 2 HR response during exercise was also a non-significant risk factor in mortality.

Association of high-density-lipoprotein cholesterol with mortality and other risk factors for major chronic noncommunicable diseases in samples of US and Russian men.

Previous reports from the Russian Lipid Research Clinics (LRC) study showed no association between the level of high-density-lipoprotein (HDL) cholesterol and mortality from coronary heart disease (CHD), while US LRC data indicated a strong negative association between HDL cholesterol and CHD mortality. This report investigated the association of HDL cholesterol and mortality in these same population samples with follow-up extended to 12 years. The association between HDL cholesterol and mortality remained inverse and significant in the US sample. In the Russian sample, high levels of HDL cholesterol were associated with higher risk of all-cause and cancer mortality, although adjustment for known risk factors reduced the strength of the association. The association between HDL cholesterol and CHD mortality was negative in the Russian sample, although the strength of the association was less than that for the US sample. Extended follow-up reduced the difference in the association between HDL cholesterol and mortality between the two countries; however, important differences remained. Further research will be required to clearly determine the cause for their differences.

Comparative effectiveness of visual/tactile and simplified screening examinations in caries risk assessment.

Central to the development of a model for identifying children at high risk to caries is a clinical evaluation to assess dental status and other conditions potentially useful in caries prediction. Traditionally, this evaluation has been based on a relatively lengthy visual/tactile examination conducted by a dentist. Replacing the dentist examination with a dental auxiliary conducted screening evaluation could lead to reduced time and costs. The 4-yr University of North Carolina Caries Risk Assessment Study involved approximately 5000 schoolchildren initially in Grades 1 and 5 living near Aiken, South Carolina, and Portland, Maine. The effectiveness of caries prediction models using visual/tactile examination data were compared with the same models using simplified screening evaluation data. Results showed sensitivity ranged from 0.57 to 0.61 for the visual/tactile and screening models by site and grade cohort. Specificity for the models ranged from 0.80 to 0.83. None of these differences in sensitivity and specificity between visual/tactile (dentist) and screening (hygienist) models was statistically significant. Findings show that for the prediction of children at high risk to dental caries the clinical evaluation may be conducted with no reduction of precision by using dental hygienist performed screening evaluations rather than dentist conducted visual/tactile examinations. While no cost data were collected, these results imply that costs to future prediction programs could be reduced by using screening evaluations.

The University of North Carolina caries risk assessment study: caries increments of misclassified children.

The University of North Carolina caries risk assessment was conducted between 1986 and 1989 with 5000 children initially in grades 1 and 5 from low fluoride sites in South Carolina and Maine. Clinical, microbiologic, behavioral, and demographic factors served as independent variables used in logistic multiple regression models to determine the predicted caries risk classification of each child. The 3-yr DMFS increment of each child was the dependent variable, and the 20-25% of those in each cohort with the highest increment were considered the high risk group. Sensitivity and specificity values averaged 0.60 and 0.83 respectively, indicating the misclassification of substantial numbers of children. This paper reports analysis of the DMFS increments of the misclassified children. The majority of children had DMFS increments within one or two surfaces of the classification cut points. Many false negative children had increments composed entirely of filled surfaces, often of minimal extent and without evidence of previous decay. Many false positive children had increments composed of decayed surfaces and would have benefitted from being identified as high risk and assigned to a preventive program. Other false positive children had sealants placed after the baseline examination that undoubtedly reduced their true increment. It is concluded that the consequences of misclassification are not serious for most children in this study.

Poland-US collaborative study on cardiovascular epidemiology: classification agreement between US National Cholesterol Education Program and European Atherosclerosis Society hyperlipidemia guidelines in selected Polish and US populations.

Data from two epidemiological studies are used to measure the degree to which two well-known guidelines agree in measuring hyperlipidemia in population samples in the US and Poland. The epidemiological studies are the US Lipid Research Clinics Program Prevalence Study and the Pol-MONICA project in Poland and the guidelines are those adopted by the US National Cholesterol Program (USNCEP) and by the European Atherosclerosis Society (EAS). EAS guidelines were analyzed in two ways: Method 1 used triglycerides and total cholesterol only in classifying persons as hyperlipidemics or non-hyperlipidemics; Method 2 used triglycerides, total cholesterol and nine additional risk factors in the classification process. USNCEP guidelines used total cholesterol, low density lipoprotein cholesterol and the same additional nine risk factors used in EAS Method 2 in classifying hyperlipidemics. Classification differences between the two sets of guidelines were high when EAS Method 1 guidelines were compared with USNCEP guidelines. However, EAS Method 2 which included risk factors, compared favorably with USNCEP guidelines in all three populations under study.

The University of North Carolina Caries Risk Assessment study: further developments in caries risk prediction.

Over 4000 first and fifth grade children from the areas surrounding Aiken, South Carolina, and Portland, Maine, participated in a 4-yr study to develop caries risk assessment models. The predictors used at baseline included detailed clinical examinations, salivary microbiological tests, and sociodemographic and dental behavior data. Mean 3-yr caries increments in South Carolina were twice those in Maine. For the four risk assessment models (two grade cohorts at two sites) specificity values averaged 0.83 and sensitivity values averaged 0.60. Clinical predictors such as prior DMFS, pit and fissure morphology, and predicted caries risk status were the major contributors to the models.

Risk assessment for oral diseases.

This paper seeks to achieve four goals, each of which forms the basis for a section in the presentation. First, the rationale of risk assessment is fully described. In this section, some of the necessary conditions are identified that make disease prediction worth pursuing. The second section discusses some essential background to the understanding of risk assessment in dentistry. In this segment, attention is focused on population-based and individual-based perspectives, alternative approaches to expressing health risk, and methods for comparing the predictive accuracy of alternative risk assessment models. The third section of the paper develops a conceptual framework for risk assessment in dentistry. Particular emphasis is devoted to the identification of risk factors and their incorporation into alternative statistical models. In the fourth section, empirical data are offered by which certain comparisons of the alternative risk models can be drawn. The paper concludes with a discussion that emphasizes data and technical limitations, speculates on future applications, and suggests new avenues for research.

University of North Carolina caries risk assessment study. III. Multiple factors in caries prevalence.

The baseline caries experienced of approximately 5,000 children in South Carolina and Maine was used as the dependent variable in caries risk assessment analyses. Clinical, microbiologic, and demographic factors served as independent variables in a multivariate relationship to caries through regression and discriminant function analyses. Four factors--number of dental visits by the child in the past year, presence of white spot lesions, and both the urgency of need for restorative care and the future caries increment predicted by the examiner--associated significantly and consistently with caries prevalence in primary and permanent teeth of first and fifth graders at both study sites. Several factors associated significantly with caries prevalence at only one site or grade within a site, suggesting that wide applicability of a specific caries risk assessment model may be limited. In these analyses, sensitivity ranged from .60 to .72 and specificity varied from .86 to .91 in the four grade-site groups. The ultimate goal of this longitudinal study is to identify highly caries-prone children in time to prevent the occurrence of a future caries increment. Although the lack of consistent association of many variables, including microbiologic factors, with baseline caries prevalence was unexpected, it is expected that some of these variables will contribute predictive power in the prospective study.

The University of North Carolina Caries Risk Assessment Study. II. Baseline caries prevalence.

Baseline clinical dental examinations were conducted on 5,233 children in grades 1 or 5 from the areas surrounding Aiken, SC, and Portland, ME, as part of a longitudinal study being conducted to predict children at high risk to dental caries. Mean caries levels in the Aiken area were nearly twice those of the Portland area. Black children experienced slightly more disease than whites. In addition to lower levels of caries experience, Portland children also had more treatment needs met, as indicated by higher filled ratio scores.

Poland and US collaborative study on cardiovascular epidemiology. III. Correlates of systolic and diastolic blood pressure in men and women aged 35-64 years from selected Polish rural, Polish urban, and US samples.

Three diverse samples of men and women aged 35-64 years living in urban Poland, rural Poland, and the United States are described and subsequently analyzed using systolic blood pressure and diastolic blood pressure separately as dependent variables in multiple regression. Several demographic, behavioral, and biologic factors are included in the models as independent variables. Heart rate, Quetelet index, high density lipoprotein cholesterol, and the natural logarithm of triglycerides were statistically significant in accounting for variation in systolic pressure in men in all three samples, whereas only heart rate and Quetelet index were significant in women in all samples. In the analysis of diastolic pressure, Quetelet index, heart rate, and ethanol consumption were statistically significant in men in all three samples, while only Quetelet index and heart rate were significant in women in all samples.

Comparative effects of a 4-year fluoride mouthrinse program on high and low caries forming grade 1 children.

This paper presents the comparative effectiveness of fluoride mouthrinse (FMR) on high and low caries forming children after a 4-yr exposure to weekly rinse beginning in the first grade. Over 1200 grade 1 children drawn from both fluoride deficient and fluoridated sites were divided into treatment and concurrent, longitudinal control groups. After 4 yr these children were stratified according to caries increment; those above the 75th percentile were considered high caries formers, all others were designated low caries formers. After adjustment of the mean increments for differences in SES, age, race, and sex in rinse and control groups, high caries formers (approximately 25% of the children) in the rinse and control groups in fluoride deficient areas showed increments of 7.00 and 7.79 surfaces, respectively, indicating a savings of 0.79 surfaces. Low caries formers (approximately 75% of the children) demonstrated increments of 1.11 DMFS in the rinse group and 1.40 in the control group (savings 0.29 DMFS). The pattern was quite similar for children in fluoridated areas except that the increments, as well as the savings realized, were lower. The results raise questions as to the practical effectiveness of school based FMR programs even for high caries forming children.

Correlates of systolic and diastolic blood pressure in men 40 to 59 years of age sampled from United States of America and Union of Soviet Socialist Republics Lipid Research Clinics populations.

The correlates of blood pressure (BP) were investigated in 2 samples using common protocols, one from a Union of Soviet Socialist Republics study in 2 locations and one from a United States of America study in 9 locations. Age, heart rate, Quetelet index, high density lipoprotein cholesterol, natural logarithm of triglycerides and fasting glucose were positively related to systolic BP in both samples. In diastolic BP, alcohol consumption, heart rate, Quetelet index and natural logarithm of triglycerides were positively associated, and number of cigarettes smoked was negatively related in both samples.

Prevalence of ischemic resting and stress electrocardiographic abnormalities and angina among 40- to 59-year-old men in selected U.S. and U.S.S.R. populations.

The prevalence of electrocardiographic (ECG) abnormalities and angina was investigated in 40- to 59-year-old men from two samples, one from a U.S.S.R. study in two locations and one from a U.S. study in nine locations. ECG abnormalities were defined by the Minnesota code and angina was defined by the Rose questionnaire. No differences were found in the prevalence of major Q waves and major or minor ischemia between the two samples, but differences were found in specific indicators of major ischemia. Major ischemic changes were more prevalent in older subjects in both samples. Estimated prevalence of angina was 50% less in the U.S. sample than in the U.S.S.R. sample, and this was consistent with the proportion of subjects excluded from the exercise test because of angina. In both samples, subjects with ECG abnormalities had higher systolic blood pressures. No difference in exercise test abnormalities was found between samples; however, more subjects with a history compatible with coronary artery disease were excluded from the U.S.S.R. sample.

The University of North Carolina Caries Risk Assessment Study. I: Rationale and content.

This article presents the rationale and content of a current study that seeks to improve methods to identify children at high risk to dental caries. It summarizes the results of the development of a 12-factor, preliminary caries prediction model based on data derived from the National Preventive Demonstration Program. Despite data limitations, the model produced a sensitivity of .5 and specificity of .8 for four-year caries increment prediction in first- and fifth-grade children. Data on a number of additional potential predictors are being collected in two sites to expand and improve the existing model. These factors are identified.

Development and application of a prediction model for dental caries.

The development and validation of a caries prediction model comprising 13 sociodemographic and dental examination variables on Grade 1 and Grade 5 children in the National Preventive Dentistry Demonstration Program are described. The objective was to derive a method of predicting children at high risk to caries early in order that preventive measures might be undertaken. True high risk children were defined in two ways: highest 25% of children based on their 4-yr DMFS increment, and their total DMFS score at the end of the study. In both cases, children predicted to be at high risk were defined as the 25% with the highest discriminant score. Discriminant function and logistic regression analyses were used to determine the extent to which the 13 variables collectively discriminated between true high risk and non-high risk children so defined. Sensitivity was approximately 0.50 and specificity around 0.82, using the 4-yr increment as the criterion for defining true high risk, and approximately 0.64 and 0.88, respectively, using the final DMFS score for defining true high risk.

Application of life table methodology in determining dental caries rates.

Probabilities of caries risk over time measured from eruption of first and second molars are illustrated using life table methodology. Life table rates based on 4,365 children in the National Preventive Dentistry Demonstration Program indicate that both fluoridation and sealants are effective in preventing caries on occlusal and buccal/lingual surfaces of molars. Effectiveness would probably have been greater on occlusal surfaces if sealants had been applied closer to the time of eruption. Similarities and differences between conventional DMFS indices and life table probabilities are discussed.

Identifying children who will experience high caries increments.

An 18-month longitudinal study of 197 5 to 18-yr-old children was conducted to assess the performance of multiple baseline variables in predicting which children would experience high increments of caries. Nine predictors were assessed; DMFS and defs scores, number of permanent teeth, indices of fissure retentiveness and occlusal morphology, S. mutans and lactobacilli levels, and sex and race. Discriminant analyses were applied to data for children in five age groups to identify the 30% who would have the largest 18-month DMFS increments. Prediction performance was assessed by comparisons with the actual high increment group, defined as those children with increments in the upper quartiles of the DMFS distributions within age groups. The analyses predicted between 56% and 91% of actual high increment children depending on age group. The children identified in the analyses experienced between 59% and 91% of the disease experienced by the actual high increment groups.

Recent dental caries and treatment patterns in US children.

This report presents dental caries and treatment patterns found in a longitudinal study of US children between 1978 and 1982 who were geographically dispersed across several fluoridated and nonfluoridated sites. The analyses include first- and fifth-grade children examined annually for four years in the National Preventive Dentistry Demonstration Program and who did not receive effective preventive procedures. The results indicate that in association with the caries decline in US children, treatment ratios increased by over 20 percent during the study period. FS/DFS ratios averaged 79 percent for the four grade/fluoridation status cohorts analyzed and were significantly higher in fluoridated than in nonfluoridated sites. The single-fissured surface was the dominant treatment or disease area observed and these surfaces tended to be restored early. In assessing tooth-surface status changes annually, tooth surfaces were more than twice as likely to change from sound to filled than from sound to decayed between yearly examinations at fluoridated sites. The lower levels of decay and higher degree of restorative care observed were not observed in lower SES and black children nearly to the extent as those for higher SES and white children in the population. The dental profession should shift its emphasis from the early restoration of fissured-surface defects to an expanded use of sealants for those with reduced decay and focus resources on a minority of the population with high caries levels who receive limited care.

A randomized prospective study of the use-effectiveness of two methods of natural family planning.

The final results of a prospective comparative study of two methods of natural family planning indicate a significant difference in the 12 month net cumulative pregnancy rates between the ovulation and symptothermal methods. These differences are on the order of two to one in favor of the symptothermal method. Pearl pregnancy rates confirm similar differentials between the two methods. Dropout rates for both methods were high. Lack of interest or dissatisfaction with the method was the major reason for dropout training while pregnancy or desire for pregnancy were the major reasons for dropout during the formal phase of the study.

PIP: In a prospective, comparative study in Los Angeles, California (1976-1978), 1247 volunteer couples were randomly assigned to either the ovulation method (OM) or the symptothermal method (STM) of natural family planning (NFP). 12-month Pearl pregnancy rates for both phases of the clinical trial (3-5 month training phase plus formal study phase) showed STM to be more effective (16.6 pregnancies/100 women-years) in preventing pregnancy than OM (34.9 pregnancies/100 women-years). For the formal study phase excluding training, Pearl rates were 13.7 for STM and 39.7 for OM. Both methods showed high dropout rates at 12 months (including training) 74% for OM and 64% for STM. Reasons given during the training phase were lack of interest or method dissatisfaction and during the study phase unplanned pregnancy. Of the 90 pregnancies that occurred during training (59 OM and 31 STM) and 62 during the study phase (42 OM and 20 STM), only 6 OM and none of the STM pregnancies were considered strictly method failures. Other pregnancies were due to inaccurate interpretation of mucus symptoms and failure to follow rules. The unexpected difficulty in recruiting couples is attributed to lack of public awareness of NFP, user satisfaction with and acceptance of other contraception methods, and an unwillingness to adhere to the formal requirements of the study protocol. Two-thirds of the 1247 volunteer couples responded to follow-up 1 year after the study. One-half were still using the NFP method they were taught. The other half had stopped because of desired pregnancy or inconvenience or dislike of the abstinence required.