Predictive equations for stature in the elderly: A study in three Latin American cities

AIM

The aim of this study was to develop predictive equations based on anthropometric data to estimate stature in people 60 years and older in Latin America.

DESIGN

Population-based cross-sectional study in three Latin American cities.

SUBJECTS

Sample sizes were n=1657 (Sao Paulo, Brazil), n=1004 (Santiago, Chile) and n=995 (Mexico City, Mexico).

METHOD

The prediction equations were fitted by stepwise linear regression analysis. For each country and sex, samples were randomly split into two sub-samples (training and validation sub-samples) using the cross-validation method.

RESULTS

Stepwise regression analysis in the training sample revealed that only knee-height and age had a significant effect on the prediction of height. The values of the shrinkage statistic were below 0.1 indicating the reliability of the prediction equations. The regression equations had standard errors of estimate ranging from 3.3 cm (Chile), 3.6 cm (Brazil) and 4.0 cm (Mexico) for women, and 3.7 cm (Mexico and Chile) and 3.8 cm (Brazil) for men.

CONCLUSIONS

Sex-specific stature prediction equations based on knee-height and age were obtained from large representative samples from selected cities of Latin America.

[Multivariate study of the evolution of body dimensions in elderly Chilean women]

Although in medical research the use of longitudinal data to analyze short time periods is frequently required, it does not permit the use of classic statistical methods for chronological series. The objective of this study is to present the possibility and plausibility of using the STATIS method (Structuration des Tableaux A Trois Indices de la Statistique), an explorative method for data analysis, in a study of the body composition of a sample of 57 women over 68 years of age in Santiago, Chile who were observed over a period of 30 months. The variables analyzed (measured every 6 months) were the following anthropometric measurements: weight, height, arm circumference, calf circumference, waist circumference, hip circumference and knee height. The results obtained suggested a regular chronological evolution during the first 24 months of observation with a change in structure after 30 months of the study, thereby classifying subjects according to body composition.

Impact of clinic interventions on the rate of influenza vaccination in pregnant women

OBJECTIVE

To assess the impact of interventions in a prenatal clinic on the influenza vaccination rate in pregnant women.

STUDY DESIGN

This retrospective study of women receiving care in a university prenatal clinic examined the impact of several interventions to increase immunization rates implemented over 2 years. Influenza vaccination rates were assessed before and after the interventions, which included provider and staff education, stocking of the vaccine in the clinic and implementation of standing orders.

RESULTS

Influenza vaccination rates in pregnant women increased from <1% to 37%. Standing orders were the most important intervention for increasing immunization rates. Patients who received care in the certified nurse midwife clinic were more likely to be vaccinated, while those who received care in a high-risk obstetric clinic were less likely.

CONCLUSION

Interventions to improve influenza vaccination rates among pregnant women, particularly standing orders, are effective. These interventions should be implemented nationally in all prenatal care clinics.

Indicadores antropométricos, composición corporal y limitaciones funcionales en ancianos

BACKGROUND

Functional limitations limit the independence and jeopardize the quality of life of elderly subjects.

AIM

To assess the association between anthropometric measures and body composition with functional limitations in community-living older people.

MATERIAL AND METHODS

Cross-sectional survey of 377 people > or = 6 5 years old (238 women), randomly selected from the SABE/Chile project. Complete anthropometric measurements were done. Handgrip muscle strength was measured using dynamometers. Body composition was determined using Dual-Energy X-Ray Absorptiometry. Functional limitations were assessed using self reported and observed activities.

RESULTS

Body mass index was strongly associated with fat mass (men r =0.87; women r =0.91) and with lean mass (men r =0.55; women r =0.62). Males had significantly greater lean mass (48.9 kg vs 34.9 kg), and bone mass than females (2.6 kg vs 1.8 kg) and women had higher fat mass than men (26.3 kg vs 22.9 kg). The prevalence of functional limitations was high, affecting more women than men (63.7% vs 37.5%, p <0.01). Functional limitations were associated with lower handgrip strength in both sexes. In the multiple regression models, with functional limitations as dependent variable and anthropometric measures as contributing variables, only hand grip strength had a significant association (negative) with functional limitations in both genders. Age was also a significant risk factor for functional limitations among women.

CONCLUSIONS

Hand grip strength was strongly and inversely associated with functional limitations. Handgrip dynamometry is an easy, cheap and low time-consuming indicator for the assessment of functional limitations and the evaluation of geriatric interventions aimed to improve functional ability.

Anthropometric measurements in the elderly population of Santiago, Chile

OBJECTIVE

There are few studies on anthropometry and nutritional status in large and representative samples of elderly populations in Chile and South America. We describe age and sex differences in weight, height, body mass index, knee height, waist circumference, midarm circumference, triceps skinfold thickness, arm muscle area, and calf circumference in Chilean elderly subjects.

METHODS

This was a population-based, cross-sectional study. A total of 1220 elderly persons (819 women and 411 men; age range, 60-99 y) were recruited in the city of Santiago (Chile) through a probabilistic sampling procedure carried out from October to December 1999.

RESULTS

Men were significantly heavier and taller than women in all age groups, whereas body mass index values were significantly higher in women than in men. All anthropometric variables showed a decrease in average values with aging in men and women. The apparent negative slopes for the decline in average values of body weight with aging was of greater magnitude in women than in men (-0.42 kg/y and -0.54 kg/y in male and female subjects, respectively). However, significant age x sex interaction was detected only for triceps skinfold thickness. In women, quadratic terms for age provided a significantly better fit than did the simple linear model for the association between age and weight, body mass index, waist circumference, triceps skinfold thickness, calf circumference, or midarm circumference.

CONCLUSION

These observations indicated that body weight changes associated with aging might be more severe in Chilean women than in men, probably determining a differential pattern of lean and fat mass loss.

Polymorphisms in candidate genes for type 2 diabetes mellitus in a Mexican population with metabolic syndrome findings

The metabolic or insulin resistance syndrome, characterized by hypertension, dyslipidemia, glucose intolerance and hyperinsulinemia, may have genetic determinants. The insulin gene (INS), insulin receptor gene (INSR) and insulin receptor substrate 1 gene (IRS1) have been proposed as candidate genes. We examined eight polymorphisms in these genes in 163 individuals from Yucatan, Mexico; this population has a high prevalence of obesity, type 2 diabetes mellitus and dyslipidemia. Subjects were evaluated for body mass index (BMI) and blood pressure. Blood samples were collected to determine glucose, insulin, triglycerides and cholesterol levels, as well as for DNA isolation. Restriction fragment length polymorphisms in INS, INSR and IRS1 were identified by polymerase chain reaction and digestion with selected restriction enzymes. Among the eight polymorphisms analyzed, the PstI polymorphism in INS was significantly associated with hypertriglyceridemia and with the presence of at least one abnormality related to the metabolic syndrome (P=0.007 and 0.004, respectively). The MaeIII polymorphism in INS was associated with fasting hyperinsulinemia (P=0.045). In multilocus analyses including both INS polymorphisms, significant associations were seen with hypertriglyceridemia (P=0.006), hypercholesterolemia (P=0.031) and with presence of at least one metabolic abnormality (P=0.009). None of the polymorphisms in INSR or IRS1 was associated with any of these traits. These findings suggest that the insulin gene may be an important determinant of metabolic syndrome, and particularly of dyslipidemia, in this population.

Research trends in mother-child healthcare, 1966-1995

OBJECTIVE

To explore trends in mother-child healthcare (MCHC) research over the past 30 years.

METHODS

Classifications of Medline articles were made at 5-year intervals using Medical Subject Headings (MeSH) as classifiers. Papers were classified in mutually and non-mutually exclusive categories by subject (mother and four age groups of children) and type of research (clinical, basic, epidemiologic, and unclassified) and its various combinations.

RESULTS

The number of MCHC papers increased from 34,110 in 1966 to 65,028 in 1995, but the proportion of all Medline articles (18-21%) was relatively stable. There were remarkable long-term temporal stabilities in the proportions of MCHC papers of mothers and the four age groups of children. Most papers dealt with child (46%) and adolescents (45%), and only 11% studied mother and children together. Regression analysis indicated that a linear increase in number of MCHC papers in Medline (1053/year) was represented largely by single-age and combinations of age children, especially adolescence. However, the slope for mother-plus-children papers (113/year) was substantially higher than for mothers alone (64/year). Clinical papers (52%) were the dominant type of MCHC research, but the proportions of basic and epidemiologic papers and their combinations with clinical papers have increased substantially in the past decade.

CONCLUSIONS

There has been a dominance of clinical and child-related papers in MCHC research, which may be a reflection of restricted outlooks of specialists in the area. This may change soon if the tendency toward increasing numbers of basic and epidemiologic papers holds.

Prevalence of pre-obesity and obesity in urban adult Mexicans in comparison with other large surveys

OBJECTIVE

1. To estimate the prevalence of pre-obesity and obesity in a 1992 to 1993 national survey of the Mexican urban adult population. 2. To compare our findings with other national surveys and with data for Mexican Americans.

RESEARCH METHODS AND PROCEDURES

The national representative sample of the Mexican urban adult population included 8462 women and 5929 men aged 20 to 69 years from 417 towns of >2500 people. Body mass index (BMI), calculated from measured weight and height, was classified using the World Health Organization categories of underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5 to 24.9 kg/m2), pre-obesity (PreOB = BMI 25 to 29.9 kg/m2) and obesity (OB = BMI 30+ kg/m2). Estimates for Mexican Americans were calculated from U.S. survey data.

RESULTS

Overall, 38% of the Mexican urban adult population were classified as pre-obese and 21% as obese. Men had a higher prevalence of pre-obesity than women did at all ages, but women had higher values of obesity. Both pre-obesity and obesity increased with age up to the age range brackets of 40 to 49 or 50 to 59 years for both men and women. Both pre-obesity and obesity prevalence estimates were remarkably similar to data for Mexican Americans from 1982 through 1984. Comparison with other large surveys showed that countries differed more in the prevalence of obesity than of pre-obesity, leading to differences in the PreOB/OB ratio, and that countries also differed in the gender ratio (female/male) for both pre-obesity and obesity.

DISCUSSION

Pre-obesity and obesity were high in our population and increased with age. Our approach of characterizing large surveys by PreOB/OB and gender ratios appeared promising.

[Relationship between leptin and insulin blood levels in obese and lean Chilean women]

BACKGROUND

Leptin, a product of ob gene and insulin blood levels, are proportional to the amount of adipose tissue. Insulin could have an independent regulatory effect on leptin secretion.

AIM

To assess the relationship between serum leptin and plasma insulin levels in obese and lean Chilean women.

MATERIAL AND METHODS

One hundred forty five women, aged 20 to 60 years old, were studied. Weight, height, waist and hip circumference, fasting blood glucose, insulin and leptin levels were measured. Insulin resistance was assessed using the homeostasis model assessment. The relationship between different variables was determined using multiple linear regression, variance analysis and non parametric correlation.

RESULTS

Leptin serum concentrations were positively correlated with body mass index, insulin plasma levels and degree of insulin resistance. The association of leptin with insulin was independent of body mass index and persisted after adjustments by body fat distribution and age.

CONCLUSIONS

Insulin and insulin resistance are associated to high blood leptin levels and this association is independent of the degree of adiposity and body fat distribution.

Hypertension in urban Mexico: the 1992-93 national survey of chronic diseases

The purpose of this work is to estimate the prevalence of hypertension in the urban population of Mexico. We studied a multistage national sample representative of the urban population in 417 cities of over 2500 people. The blood pressure of 14 657 individuals (6053 men and 8604 women) aged 20-69 years was measured after a 5-min rest using a standard mercury sphygmomanometer. The survey personnel had been previously trained and standardised. The main results show a crude prevalence of hypertension, as defined by the JNC VI, of 28.1% in women and 37.5% in men (27.2% and 37.1% age-adjusted). Both genders exhibited a trend of increasing hypertension with age. In individuals under 50 years of age, women had lower rates than men, but the difference disappeared in the older groups. The awareness of hypertension (28%) as well as the success of treatment (22%) were low in our sample. Our results had more similarities than differences with respect to those observed in other national surveys. It is concluded that hypertension in Mexico is an important public health problem similar to that seen in developing and developed nations. Efforts should be aimed at strengthening measures to prevent and control hypertension in Mexico. More information is needed of the sort obtained from longitudinal studies.

[Clinical nutrition training in medical schools of Mexico]

OBJECTIVE

To describe the efforts carried out to strengthen nutrition education in Mexican medical schools. Emphasis was placed on the status previous to the program implementation, the design of a new basic curriculum, and the description of the main program strategies implemented.

METHODS

a) Analysis of available medical curricula; b) Application of a questionnaire to the school deans; c) Assessment of knowledge of nutrition of advanced medical students; d) Design of a basic curriculum of clinical nutrition; e) Edition of a textbook; f) Design and implementation of program strategies to strengthen nutrition education.

RESULTS

Clinical nutrition was not a topic included in most curricula analyzed and, when present, it was incorporated to related clinical subjects. Usually, emphasis was placed on basic topics of nutrition while clinical and applied subjects were considered less frequently. Lack of a specialized faculty and weakness of teaching infrastructure were some problems identified. A basic curriculum adaptable to different contexts was designed, and a textbook on clinical nutrition was edited and published. Training and formation of nutrition specialists were among the key programs implemented.

[What is known about micronutrients in Mexico]

OBJECTIVE

To update the information on micronutrients in Mexico regarding: 1. The research lines according to priority of the micronutrient, subjects affected, and its focus (basic, clinical, epidemiological, operational). 2. The laboratory capacity available for micronutrient assays.

MATERIAL AND METHODS

We analyzed review articles of what has been published on micronutrients in Mexico since 1950. We also gathered information by questionnaire from the 16 research groups working in Mexico in the area of micronutrients.

RESULTS

We generated tables summarizing the situation of the six micronutrients which we identified as the most problematic in Mexico (vitamins A and C, and iron, iodine, zinc and calcium).

CONCLUSIONS

We reached 10 conclusions related to populations of study, research line priorities, and desirable operational studies.

Distortionless interferogram recording by use of holographic field lenses for fluid velocimetry

Two optical systems based on holographic field lenses are presented. They have been specifically designed for the CCD camera acquisition of the interferograms obtained from a fluid plane, when one uses holographic interferometry to measure fluid velocities. The use of these systems allows for easy recording of interferograms, all having the same size and position on the CCD, independent of the fluid-plane observation direction. The holographic lenses act as directional field lenses; they change the divergent beam that reaches the lens into a convergent beam that focuses on the camera aperture. These distortionless interferogram recording systems have been demonstrated in a Rayleigh-Bénard convective flow.