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Seasonality in health and nutrition on a Guatemalan coffee plantation

V. Valverde, H. Delgado, R. Flores, and R. Sibrián
Institute of Nutrition of Central America and Panama (INCAP), Guatemala City, Guatemala

This study, which focuses on a plantation, as well as the study by Bidinger et al., which concerns a village, failed to find the marked seasonal changes in food consumption reported for many other parts of the world. It would be a serious mistake to consider that these studies contradict in any way the findings of those who report seasonal variations They are published, however, as a reminder that generalizations cannot be used to predict specific cases and that, conversely, great caution must be used in generalizing from specific cases. The characteristics of the sites in both studies offer adequate explanation of why they did not fit the expected pattern of seasonal variation despite distinct rainy and dry seasons and harvest and non-harvest periods. It should be noted, however, that both Valverde et al. and Bidinger et al. did observe the anticipated marked seasonal differences in morbidity from diarrhoeal and other infectious diseases.

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For as long as fifty years, investigations have documented the growth of children in developed countries and have found that height and weight gains differ during the winter, spring, and summer months [8, 14]. Recent reviews of studies dealing with seasonal patterns in children's growth in developed countries have been summarized by Marshall [8] and Shull et al. [19].

One of the first reports of seasonal effects on food availability at the household level in developing countries was that of Fortes and Fortes [5], who described the effect of the agricultural cycle on food consumption in a Sudanic zone of Ghana. In April and May, food stores are low, while the peak of the hungry season takes place in June. In July, people cut and eat ripe millet and consume groundnuts and pulses in large quantities. During the post-harvest season, from October to December, large quantities of food are available. In January, rationing of millet begins again and becomes more severe in February and in the subsequent months until the next harvest. Moody, tracing the patterns of malnutrition in children under 5, has observed a similar agricultural pattern in northern Ghana [13].

The scientific literature concerning seasonal effects on food availability, food consumption, birth weight, children's growth, mortality, and morbidity during the 1950s, 1960s, and 1970s in Africa is abundant [2, 6,10-13,15-17, 23] and has been summarized by Longhurst and Payne [7] and Valverde et al. [22]. In general, rainy and pre-harvest months are each associated separately with a peak in the incidence of disease as well as lower energy and nutrient intakes. In African, Asian, and Latin American countries there is a higher incidence of disease during the rainy months, which usually coincide with the lean or hungry pre-harvest months. Thus, in agricultural communities in developing nations, lower intakes of energy and nutrients and less efficient utilization of energy and nutrients consumed may interact to produce detrimental seasonal impacts on children's health and nutritional status.

Flores and Flores [4] have recently reviewed the findings derived from studies on seasonality carried out since the 1950s in Mesoamerica and have also analysed their own food consumption data gathered in rural Guatemala in the 1970s. These authors called our attention to the fact that while some countries in the Western Hemisphere have four seasons, those located in the tropics are limited to two seasons: the rainy season begins in May and ends in late October; the dry season starts in November and ends in April. They have concluded that in Mesoamerica:

1. There is seasonal variation in food availability in different countries, but the effects on food consumption and nutritional status are not very clear even in poor rural areas.
2. Dramatic seasonal effects during critical periods, as expected in poor areas, are not observed owing to the ability of families to generate some income by means of social or economic mechanisms.
3. In the rural areas of developing agricultural countries, the social and economic structures, as well as agricultural systems, marketing systems, and policies, may have worse consequences than seasonal cycles. The low purchasing power of families in these areas and the poor or non-existent health and medical services will have a more detrimental effect, especially during abnormal seasonal changes [4].

The following section summarizes the findings of a longitudinal nutrition and health study carried out by INCAP staff from 1977 to 1981 in Western Guatemala [2, 3, 20, 21]. The study population was made up of permanent residents of 11 coffee plantations where the head of the household was usually employed throughout the year. Other family members (wife and children) resided within the plantations and had seasonal employment during the coffee harvest. Anthropometric longitudinal data, gathered during one year (June 1977 to May 1978) in children from birth to 60 months, were expressed as percentages of children in Gomez classification categories of weight for age, length for age, and height for age [20]. Trimestral and semestral increments in length, height, and weight for children less than 29 months and from 30 to 60 months of age were calculated.

The results of growth retardation comparisons showed no differences in the nutritional status of children for either the rainy season versus the dry season or the coffee plantation harvest period versus the non-harvest period. Comparisons of increments in weight, length, and height for the same time periods did not show a pattern of growth specific to any season or period. The findings on the effects of the harvest on children's growth from Guatemalan coffee-growing areas were not in agreement with the assumptions based on non-quantitative observations derived from studies carried out on coffee plantations in Costa Rica and El Salvador.

The following are possible explanations for these unexpected results [20]. First, Indian mothers on the coffee farms of Guatemala, as opposed to their counterparts in Costa Rica and El Salvador, do not leave small children at home during the harvest, but take them to the field. Second, the already existing high levels of malnutrition and deprivation in the Guatemalan coffee farms all year round make it difficult to isolate periods of the year during which living and health conditions are poorer than at other times and lead to poorer growth as well. Third, financial factors, such as access to loans from plantations and other alternatives exercised by families to establish savings, might help alleviate seasonal crises throughout the year.

Several methodological issues were not addressed in the earlier report [20]. Although anthropometric data were collected longitudinally, the analyses by periods were not conducted in the same cohort of children. Moreover, interactions for coffee harvest, non-harvest, rainy, and non-rainy periods were not explored. Finally, morbidity and food consumption data from families, mothers, and children were not available for a more comprehensive analysis

Delgado et al. used data from a one-year period (October 1977 to September 1978), for children aged 0-24 months from the same longitudinal study, to address the interrelate of diarrhoeal diseases and children's growth [2]. Marked differences between various periods of one year (October to December, January to March, April to June, and July to September) were observed in the incidence of diarrhoeal disease. Simple diarrhoea reached peaks during periods that included the rainy months (April to June and July to September). But while a distinct pattern emerged with respect to the incidence of diarrhoeal diseases, no clear-cut assertions could be made regarding the relationship between rainy and dry periods and anthropometric differences in children's growth. The work by Delgado et al. used distinct cohorts of children in the different periods analysed and did not address the potential interaction of harvest, non-harvest, rainy, and non-rainy periods.

Rationale for the present analyses

The availability of the longitudinal health and nutrition data provided the motivation for the present investigation. The data set contained anthropometric, morbidity, energy intake, and protein-intake measurements collected for 12 to 24 months for children from birth to 60 months of age and for their families and mothers during the same periods. These data were used to explore the main effects and interactions of seasonal events on fluctuations in family food availability, disease prevalence, and food consumption and growth in children under five years of age. The coffee harvest and non-harvest periods and the rainy and non rainy months and their potential influence on consumption, morbidity, and growth were studied.

During the coffee harvest, from August to late January, the study families exhibited a substantial increase in income, which, as one would expect, provided an important positive impact on energy and protein intakes. However, the increase in labour opportunities for mothers and older children might also mean that mothers have less time available to devote to their own health and nutritional care as well as to that of their children. The rainy season, which includes the months from May until late October, may increase morbidity, and this may exert a negative impact on children's growth. Therefore, the periods when these seasonal events are exerting their expected positive or negative combined effects will also be analysed.

Research objectives and hypotheses

This report will explore the impact and interrelationships, at the family level, of coffee plantation harvest and non" harvest periods and of rainy and dry periods on family food consumption, and subsequent impacts on children's food consumption, children's morbidity patterns, and children's growth, using data gathered from families of permanent labourers residing on coffee plantations in western Guatemala.

Materials and methods

This section describes the study population, the data set, and the analytical approach used.

Description of the Study Site

The study site, Finca Mocá, has a population of 1,318 inhabitants, and is one of 11 coffee plantations (fincas) in a region in western Guatemala that forms part of the Boca Costa. The Boca Costa runs north to south from the Mexican to the Salvadorian border and west to east from the end of the coastal plains to the volcanic mountains. The elevation ranges from 500 to 1,000 meters above sea level and there is a mean annual maximum temperature of 33°C. In 1976, rainfall ranged from 25 mm in March to 378.8 mm in June. Soils are tropical and semi-tropical and support the growth of such crops as coffee, sugar cane, tea, quinine, bananas, cardamom, pepper, citronella, and rubber. Some land is also devoted to cattle raising.

There are two seasons in the year. The dry season runs from November to April, and the rainy season from May until the end of October. Coffee is harvested from August until the end of January and provides work for all family members, including women and children. During the remaining months of the year, February to the end of July, only the head of the household is employed permanently by the plantations.

Characteristics of Populations Residing on Coffee Plantations

Two distinct population groups are found on the 11 plantations: permanent residents who live and work there throughout the year and are called colonos, and migrant labourers or cuadrilleros, who are usually hired for the coffee harvest season or part of it.

Eighty-five per cent of the colonos are of Indian extraction and 15 per cent are considered ladinos (non-indigenous, Spanish-speaking people). Most residents speak Spanish reasonably well, but their life-styles, beliefs, and attitudes are similar to those of the highland Indian communities of Guatemala.

Around 90 per cent of the families are Catholic and 78 per cent of the heads of households are married or living together in stable unions. Only 30 per cent of the population over 10 years of age is literate. The median number of years of school attendance is zero with a mean of 0.8 years.

Within each plantation all the houses are usually identical in construction and are built close together. However, there are some variations among plantations in style and construction materials. Bricks, sticks, or cement are used for the walls, zinc, asbestos, or tile for the roofs, and cement for some of the floors. All of the houses belong to the plantation owner.

Piped water is available in all plantations, and is obtained by families from any of several public faucets or fountains located throughout the plantation. Analyses of water quality, conducted in 1977, showed heavy contamination with faecal material, which is not unexpected, as latrines are not available and people defecate in the open fields near their houses.

Food Acquisition and Economic Activities

There are some differences between plantations in the food subsidies provided for workers. In 1977, corn was sold in one plantation at US$2.08 per quintal (100 pounds, approximately 45 kg), and in another at $4.00; while in a third two pounds were given free per labour day. The rest of the plantations were selling the grain at the open market price, which varied during the year from $4.00 to $12.00 per quintal.

All plantations have at least one "mill" (nixtamal) where families take their corn every day for grinding. In some this service is free, while in others there was a charge ranging from $0.01 to $0.06 in 1977.

There are small private stores on the plantations where articles such as salt, sugar, beans, rice, soda, juice, candles, soap, cigars, and matches are sold. In some places, third class beef or pork is sold once or twice a week. Every two weeks, on pay day, vegetables, grain, clothes, and household articles are sold in an open market.

Plantation owners sometimes provide small plots of land, a quarter of a hectare, for their permanent workers to cultivate maize. Normally in this region maize is planted twice a year, and harvested in August and January. This plot usually meets the families' need for maize for only one and a half or two months of the year. Many workers raise a few chicken or pigs, but these are almost always sold rather than consumed. Some families also have small fruit and vegetable gardens.

The plantations selected for study were basically dedicated to coffee cultivation, an activity that occupies almost all available labour and produces around 90 per cent of the labourers' annual family incomes.

In 1977, when income was low from May to July, a family composed of two adults, one adolescent, and two children earned $40 per month. The economic value of a minimum cost food basket for a five-member family was somewhat above $40 per month. However, during the harvest, when their income went up, the same family could earn more than $100 per month.

Owners also provide interest-free loans to permanent workers when they are in need of extra money, as in the case of death, baptism or the marriage of relatives. These loans are repaid by the workers in small instalments, due every two weeks on pay day.

Demographic Characteristics

The age and sex characteristics of the Guatemalan population resemble those of many developing nations. The age pattern of the society can be depicted graphically as wide at the bottom and narrow at the top, reflecting the youthful nature of the population. The median age falls in

the 15 to 19-year-old age group, and the dependency ratio is 0.96. This ratio is almost equal to that of Central America as a whole (0.98) and is one of the highest in the world. Fertility rates are extremely high and the child/ woman ratio is 92.1 per cent, that is, for almost every woman 15 to 49 years old there is one child under five years of age. The crude birth rate is 49.6 per thousand and the general fertility rate indicates that in 1976 one of every four women of child-bearing age had a live birth.

Health and Nutritional Characteristics of Children

The infant mortality rate was 160 per thousand live births, and the mortality rate for children aged one to four was 36 per thousand, for the period 1970-1975.

Cross-sectional anthropometric data gathered in 1976 and 1977 for children from birth to 60 months of age demonstrate a high prevalence of growth retardation. The proportion of children with second- and third-degree malnutrition, according to the Gomez classification, was 33 per cent. In a national rural anthropometric survey conducted on children from 6 to 59 months in 1977, 32 per cent fell into the Gomez classifications of second- and third-degree malnutrition [18]. Runny nose, cough, diarrhoeal anorexia, and fever had prevalence rates of more than 20 per cent in children from birth to 24 months and more than 14 per cent in older children. These values are, in general, much higher than the prevalence rates for these disorders reported for other Guatemalan populations [18]. The prevalence rates for diarrhoea were 23.3 per cent in children from birth to 24 months and 19.5 per cent in older children. The latter figures corroborate the anthropometric information that suggested that the health and nutrition problems in the study area were alarming in nature when INCAP undertook its medical care activities in 1976 as part of a longitudinal health and nutrition study.

The Data Sat

One hundred and seventy families with children under five years of age were studied in Finca Mocá from 1 October 1977 to 1 November 1979.

The variables used for the present analyses are summarized in table 1, the data collection procedures have been described elsewhere [3, 21]. Briefly, a combination of 24 hour recall and weighing methods was used to gather food consumption data from families, mothers, and children during household visits. The intervals between the collection of data on food consumption varied according to the phase of the study. For the first four months data were collected monthly; from the fourth month to the end of the first year collections were made every two months.

TABLE 1. Variables used for Finca Mocá analyses

TABLE 2. Arrangements by periods of the longitudinal data

During the second year food consumption data were collected every three months.

The field personnel collecting data had been trained using standardized protocols-a quality control system, which also included periodic standardization exercises. Experienced field personnel at the clinic made weight and length measurements for all children under 60 months of age. The infantometer had steps of 0.1 cm; weight measurements were obtained to the nearest 0.1 kg in a Detecto beam scale. Clothes worn by the study subjects were minimal and of a known weight value which could be subtracted from the weight of the subject. Anthropometric measurements were collected at birth, at 15 days of age, and at 3,6, 9, 12, 18, 21, 24, 27, 30, 33, 36, 42, 48, 54, and 60 months of age.

Morbidity information was collected for the entire year during fortnightly household visits when the mother or the person responsible for the children was interviewed regarding signs and symptoms of diseases in the children during the previous two weeks.

As presented in table 2, the 24-month longitudinal data set from Finca Mocá was arranged in eight periods, taking into account the presence or absence of rain and harvest. Thus, during the study period used here (24 months), there are four different periods in each year that include the same months in year 1 and year 2.

Analytical Strategy Used

The proposed independent variables were seasons (harvest, non-harvest, rain and non-rainy periods), years (1 or 2), and children's ages. The proposed dependent variables were family consumption of calories and protein, children's energy and protein intakes, days of illness in children, and children's growth. The interrelationships of the dependent variables were to be explored by regression analyses.

To determine the statistical significance of the observed differences in food consumption across seasons and years, analyses of variance (ANOVAs) were used for family consumption data. Analyses of co-variance (ANCOVAs) with age as co-variable were applied to data related to children's consumption of foods.

For morbidity events a one-year file (1977 to 1978) of 170 children was used to determine the incidence of nasal secretion, diarrhoea, cough, fever, and stools with blood and mucus. Analyses of the data disaggregated by age groups were also performed. The anthropometric effects of seasons were determined using a group of 19 children who had eight complete trimestral anthropometric measurements in the 24-month study period. Table 3 summarizes the periods included in the analyses for the different variables and the kinds of observations used.

The selected analytical approach used analyses of variance (ANOVAs) to determine whether rainy, non-rainy, harvest, and non-harvest periods exerted any influence on families' and mothers' consumption of foods and on their energy and protein intakes. ANOVAs were also used to determine seasonal variations in the cumulative incidence of major signs and symptoms of disease. On the other hand, analyses of co-variance (ANCOVAs) were carried out, using age as a co-variate, for energy and protein intakes as well as for weight for age, length for age, and weight for length in all children followed longitudinally for 24 months.

TABLE 3. Population samples used to address the effects of four seasonal periods per year on energy and protein intakes, food consumption morbidity events and growth

TABLE 4. Summary of ANOVAs for family energy and protein intakes with consumption

a. P<0.01.
b. P<0.001.

continue

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