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Introduction
Methodology
Main results
Interventions in Santa María Cauqué
Determinants of health
Concluding comment
Acknowledgments
References
Notes
Leonardo Mata
Editor's note:
Although
many references to published papers of this author are cited,
most of the material in this chapter can be found in the book The
Children of Santa María Canqué. A Prospective Field Study of
Health and Growth by Leonardo Mata which is highly
recommended for persons desiring more detailed information on
this remarkable study.
The study discussed in this
chapter is described in detail with multiple photographs,
figures, tables and references in the book The Children of
Santa María Canqué: A Prospective Field Study of Health and
Growth (Mate, 1978a). The study was carried out from 1963
through 1972 in Santa María Cauqué, a Maya Cakchiquel Indian
village in the central Guatemalan highlands (Figure 1). Prior to
this study, the community was the "infection control"
in the pioneer three-village study of nutrition and infection
interactions in 1959-1962 (Scrimshaw et al., 1967a,b). The other
villages were Santa Catarina Barahona (the nutrition control) and
Santa Cruz Balanyá (the nonintervened control). The Health
Clinic in Santa María Cauqué, supported by the Ministry of
Health and the Institute of Nutrition of Central America and
Panama (INCAP), was expanded in 1963 to facilitate more detailed
epidemiological observations, laboratory studies, and medical
therapy. The primary data management was carried out directly at
the village; final editing, filing, and analysis of data were
performed at the Division of Environmental Biology of INCAP in
Guatemala City and the Division of Biostatistics of the School of
Public Health and Community Medicine of the University of
Washington in Seattle. The conceptual idea, objectives, results,
and significance of the study have been published in book form.
This article summarizes the main scientific results of the study,
and their implications for modern public health and human
development.
The Human Laboratory
The study consisted of a long-term prospective observation of all cohorts of mothers and infants of the village from 1963 through 1972. Such a "human laboratory" permitted biological and sociological data to be gathered on all child cohorts during the study period, although virtually every other person in the community contributed data at one time or another. Most treatments were prescribed in accordance with Western medical guidelines and ethics. The study favored observation of the natural course of infectious disease with little disturbance, a situation difficult to replicate today.
FIGURE 1Map of central Guatemala showing the distribution of highland Indian villages where INCAP carried out field studies. Santa Cruz Balanyá, Santa Catarina Barahona, and Santa María Canqué were involved in the field study of nutrition and infection (1959-1963). Santa María continued as the village for detailed studies of infectious diseases and malnutrition Cauqué, Study) (1963-1972) and later for the maize fortification study (1972- 1975). Additional research on diarrhea! diseases was recently pursued in Santa María de Jesus.
The Health Clinic
The first year (1963) was devoted to getting acquainted with authorities, leaders, and village folk. The treatment protocol and standard operation procedure for field and laboratory were produced and tested. Virtually every pregnant woman was included in yearly cohorts for studies at the clinic or in their homes when there was illness. Smallpox had been eradicated in Guatemala before the study began. Expanded immunization for bacillus Calmette-Guérin (BCG) and diphtheria-pertussis-tetanus (DPT) was nonexistent. These vaccines were often rejected by villagers, but coverage improved through the study period. Vaccines against measles, rubella, and mumps were nor available. The first one-shot national measles immunization campaign was conducted in 1972, the year the Canqué study ended (Mate et al., 1974). More than 95% of children under five developed significant measles antibody titers according to pre and post vaccination representative samples. Measles mortality fell from the precampaign rate of 59 to 4.7 per 100,000 one year after the campaign. Lives were saved by measures of Western medicine. Penicillin was used to treat complicated respiratory infections and other suspected bacterial diseases. Sulfonamides were given for urinary tract infections and other illnesses. Continued breast-feeding was encouraged during attacks of infectious disease and convalescence. Traditional home beverages and intravenous fluid therapy were used to treat dehydrating infectious diseases. Implementation of Western medicine at the clinic was favored by the absence of an Indian shaman at the time of the study. Two pediatricians (Carlos Beteta, 1963-1965; Juan Urrutia, 1965-1974) contributed importantly to the improved health and reduced mortality attained during the study.
Cohorts of Pregnant Women
Pregnant women were the most assiduous in visiting the clinic. Although speaking the local Cakchiquel, they knew sufficient Spanish to communicate with the staff. Vaginal examinations were excluded from the protocol because they were not culturally acceptable. Blood pressure, urinalysis (including bacterial culture and test for pregnancy hormone), and diagnosis for sexually transmitted diseases were carried out. Dietary studies by recall and direct measurement were conducted each trimester.
Examination for intestinal parasites, bacteria, and viruses were performed during pregnancy on most women.
The date of birth was approximated from the date of the last menstruation and uterine height. contact between women, midwives, Ad staff favored identification of impending deliveries. These were assisted by two experienced folk midwives from the village, who collaborated as if they were members of the study team. Auxiliary nurses, posted at the Health Clinic around the clock, observed most of the deliveries during the study period.
Cohorts of Children
The nurses recorded the characteristics of each birth and newborn baby. Babies were examined by the pediatrician soon after birth, and within 1415 hours if born at night. The physician also examined the mothers. All yearly cohorts of children were studied from 1964 through 1972. All the newborns were measured at birth (weight, length, circumference of head and thorax), then daily (weight) for one week, and weekly (weight, length) for one month. Most clinical, dietary, and anthropometric appraisals and collection of laboratory specimens were conducted in the homes. Onset and duration of breast-feeding and weaning were recorded for all. Colostrum and milk were collected from a series of women to determine concentrations of secretory immunoglobulin A (S-IgA) and antibodies to selected pathogenic agents. Hemoglobin and other limited parameters were studied in only a small group of children, because drawing of blood was not readily accepted by villagers. Most newborns appeared healthy and almost all were quite protected from disease during the first weeks of life.
Intensive Cohort
A cohort of 45 children was retrospectively and randomly selected from the children born in the first two years of the study, when the oldest was 18 months of age. Clinical examination and anthropometry were carried out at birth (as above), fortnightly (weight, length, head and thorax circumference) from one month to one year of age, monthly up to age two years, and thereafter at three-month intervals until termination of the study, when the oldest child was nearly eight years old. Weekly dietary investigations by recall were conducted from birth to age three years. All acute and chronic episodes of infectious diseases were recorded for the first three years of life. Fever was measured by thermometer, and anorexia was deduced from the interview with the mother. Illnesses were diagnosed according to standard criteria. This included number of bowel movements per day, duration, recurrence of episodes, and appearance of blood and mucus in stools. Fecal specimens were obtained daily for the first week of life, and weekly thereafter until the end of the third year of life. Stools were brought to the clinic by nurses and relatives within one hour of evacuation. Cultures and other procedures were performed at the clinic's field laboratory.
Cultures taken at the village were processed in the field laboratory, and aliquots were refrigerated or suspended for processing at INCAP's laboratories. Most enteric viruses, bacteria, and parasites known in that epoch were investigated. The indigenous anaerobic and facultative microflora was quantified at weekly intervals, in the field, for 12 randomly selected infants, from birth to age one year. All epidemics of infectious disease in the village were studied.
Remaining Children
The rest of the children were examined and measured with the same technique as the 45 cohort, as follows: at birth, weekly for one month, monthly for one year, and at six-month intervals until termination of the study.
Data were
recorded in the field in precoded questionnaires and were edited
at the clinic and headquarters for computer processing.
Approximately 5 million data points were accumulated for
analysis.
