High prevalence of anemia and overweight among women workers in three palm plantations in Indonesia: a cross sectional study

Abstract

Anemia is a disorder of decreased erythrocyte mass. Indonesia is one of the countries with the highest (31.2%) prevalence of anemia among women of childbearing age in Southeast Asia in 2019. Women currently play a dual role, not only as housewives but also play a role in the public sector namely working outside the home. Women workers in the oil palm plantation sector generally experience health problems such as maternal mortality rate, malnutrition, poor pregnancy care and delivery services, and anemia. The purpose of this study was to uncover nutrition situation among women workers in the oil palm plantation sector at company X, Central Kalimantan Province, company Y, Riau Province and company Z, South Papua Province. The study design was cross-sectional which involved 105 respondents of women workers selected purposively in the study areas. Data were obtained from field measurement of hemoglobin, semi quantitative food frequency questionnaire and other questionnaire. This study found that almost half (45.7%) of respondent were anemic and around 48.6% were overweight. Around 20% were both anemic and overweight. Low iron intake, low vitamin C intake, high calcium intake, multiparity, and poor physical environment condition were all significantly related to higher risk of anemia. Various causes of anemia should be considered in intervention or supplementation program. A combination of nutrition and other health surveillance would be suggested not only to alleviate but also to prevent the problem.

Introduction

Anemia is a condition of hemoglobin insufficiency to deliver oxygen to tissues [1]. Although several nutrients can cause anemia, the most common single micronutrient causing anemia is iron (Fe). When not treated, iron deficiency anemia can cause serious health issues and is mainly characterized by fatigue, lesser productivity and poor maternal health and outcomes [2].

The prevalence of anemia among productive women according to WHO data in 2019 was 29.9%. The highest prevalence was in Southeast Asia i.e. 46.3% and Indonesia was among the top ten highest prevalence of anemia in Southeast Asia with a 31.2% prevalence [3]. The prevalence of anemia among women of reproductive age in Indonesia increased from 28.9% (2016) to 29.6% (2017) and 30.4% (2018) [4].

The double role of women means women are not only active in the domestic sector but also play important roles outside home in public sector. According to the Central Statistics Bureau in 2020 around 49.7% of women aged 15 years and above were working outside the home while in 2021. The rate rose slightly to 50.1% and 50.3% in 2022 [5].

The women workforce was vulnerable to nutrition problems. Most of these problems were related to the low social and economic status of women, which drove them to the low rank of workers. These disadvantages would lead to low nutrition and health knowledge and literacy. Among these women workers, physiological factors related to menstruation (and Fe loss) were worsened by low nutrition intakes [6].

In recent years, palm plantations have been on the stage especially due to the sharp increase in cooking oil prices. Indonesia is the country with the largest palm plantation in the world. Oil palm plantations are the highest contributor to Gross Domestic Product (GDP) figures compared to other plantation sub-sectors. In 2021, 26 out of 34 provinces in Indonesia have oil palm plantations managed by the government, private sector or public sector [5]. Based on data from [7], Indonesia has 11.75 million hectares of palm plantation in 2019 or 49.5% of total plantations in the world with 42.87 million tonnes of production with a productivity of 3.7 kg/ha.

Workers of palm plantations in Indonesia generally face similar problems where they are in an unclear status of working contracts (daily paid workers, short-term contracts, outsourcing etc.) which leads to poor working conditions. They have no access to health insurance and have to work under limited facilities [8].

Another problem faced by women workers in palm plantations is associated with gender dimension particularly related to working relations and stereotypical perceptions of women workers. They also have constraints related to gender-based discrimination, vulnerabilities of women and children in plantation situations, access to reproductive health services, nutrition and food consumption problems, pregnancy and post-pregnancy care and high prevalence of anemia [8].

This study reports findings on anemia, nutritional status, nutrient intakes, and other aspects of palm plantations in three provinces in Indonesia. We believe this report is among the first to inform the nutrition and anemia situation among women workers in palm plantations in Indonesia.

Methods

This is a quantitative cross-sectional study with anemia as the dependent variable and education level, menstrual cycle, intakes of energy, protein, iron, vitamin C, calcium, fiber, folate, workload, nutrition status, and parity as independent variables. Primary data were collected through questionnaires among women workers in companies X, Y and Z in Katingan District, Central Kalimantan Province; Kampar District, Riau Province; and Merauke District, South Papua Province; respectively. Field study was implemented from November 2022 to April 2023.

Subjects were selected purposively with a total of 110 women workers selected as subjects. Five of the subjects were pregnant and were excluded from the analysis. The inclusion criteria in the selection of the subject were workers aged 18–49 years, workers who were in good health, and workers who were willing to take part in the data collection process in the research. The exclusion criteria were pregnant women and women workers who have physical disabilities and spinal disorders that can affect the results of anthropometric measurements.

Anemia was measured by a hemoglobin level cutoff of < 12 mg/dL. BMI was measured based on anthropometric measurements of height and weight categorized as “normal” (18.5–25.0 kg/m²), and “overweight” (≥ 25 kg/m²). Nutrient intake data were obtained based on a semi-quantitative food frequency questionnaire, with portion estimates provided by the respondents based on her usual portion size using common unit of measurement (such as glass, plates, tablespoon etc.). Due to feasibility of the study, no other method of dietary assessment was implemented. Other data were collected through interviews using questionnaires. Analyses were conducted to investigate the relationship between dependent and independent variables using chi-squares for bivariate and logistic regression for multivariate analysis. This research refers to code of ethics No: KET-1077/UN2.F1/ETIK/PPM.00.02/2022 and Grant Number 099/WWF-ID/LGL-GRA/VIII/FY23/2022.

Results

Most respondents (81.0%) were in the age range of 30–49 years and only a third (33.4%) had education senior high school or higher. Most respondents (87.6%) were married. Around 80.0% of respondents worked in the field and 20.0% worked in the office with a majority of them (72.4%) having worked for 5 years or more (Table 1).

Table 1 Characteristics of respondent

Almost half (45.7%) of respondents were anemic (Table 2). Around 48.6% were overweight and most (74.3%) had normal menstrual cycles. Most (68.6%) of respondents were multiparous (women who have given birth to more than one child) and more than half (61.0%) perceived that their physical environment was good. Regarding nutrient intakes, compared to Indonesian RDA (Recommended Dietary Allowances) most of the respondents had less than adequate intakes (energy less than RDA 61.9%, protein 46.7%, fiber 96.2%, folic acid 90.5%, vitamin C 61.0%, calcium 89.5%, and iron 84.8%).

Table 2 Anemia status and its determinants

Table 3 exhibits different categories based on overweight and anemia status. Although no analysis of the relationship between overweight and anemia was carried out, the table shows that respondents who were overweight and also experienced anemia was around 20.0%.

Table 3 Various category of anemia and nutritional status

Multivariable analysis (Table 4) resulted in iron intake and vitamin C intake as variables that significantly (p value < 0.05) related to anemia. The odds ratio for iron intake was 13.5 (95% CI 1.6–117.6) which means those with less than adequate (< 100% RDA) iron intake had 13.5 times higher risk of anemia than those with adequate iron intake. While the odds ratio (OR) for vitamin C was 4.6, those with less than adequate vitamin C intake had a 4.6 times higher risk of anemia compared to those with adequate vitamin C intake. On the other hand, calcium intake is negatively related to anemia with OR of 0.019 meaning that those with adequate intake of calcium had 52.6 times higher risk of anemia compared to those with less adequate calcium intake. Additionally, parity and physical environment also posed as risk factors of anemia with ORs of 3.4 and 2.8, respectively.

Table 4 Multivariate final model

Discussion

This brief report highlighted the findings of a study on anemia status among palm plantation workers on three different islands in Indonesia. As the biggest producer of palm oil, Indonesia should pay more attention to the welfare of palm plantation workers, especially amid international concerns regarding palm plantations and the palm oil trade. Study on reproductive health among plantation workers in Indonesia is still very much lacking, thus this study would be deemed important as to open the research domain and to provide first data in the issue.

Anemia data showed no surprising result as more than 45% of the women workers in this study were anemic. Anemia can be caused by several factors, including lack of nutritional intake, especially iron and other nutrients such as vitamins A, B6, B12, C, E, folic acid and riboflavin. Vitamins A, B6, B12, folic acid and riboflavin play a role in the formation of red blood cells. While antioxidant vitamins such as vitamin C and E would protect red blood cells. Accordingly, this study found that iron and vitamin C had a significant association with anemia as shown in Table 4.

This study also revealed that calcium intake was inversely related to anemia. Calcium intake is known to inhibits iron absorption. There are two ways in which calcium intake inhibit iron absorption, first, calcium limits the transportation of iron by internalization of divalent metal transporter 1 (DMT1) (DMT1 is a metal transporter which has a major role in transporting iron [9]); second, calcium blocks iron transfer through the cell membrane [10]. A previous study on the dose–response relationship between calcium intake and iron absorption revealed that a dose of more than 1000 mg would reduce iron absorption by 49.6%, while a dose of 800 mg would reduce iron absorption by 37.7% [11].

Of the non-food factors related to anemia, parity and physical environment condition were significantly related to anemia. A study by Imai found that anemia and low serum ferritin were found more frequently among multiparous women than in nulliparas [12]. In addition, short intervals between pregnancies also posed a risk factor for anemia. Regarding the physical environment, especially the working environment, women workers were exposed to various chemicals and pesticides which potentially related to a higher risk of anemia as recently highlighted by Zhou et al. [13]. Pesticides that enter the body have an impact on changes in complete blood counts such as monocytes, monocyte percentage, red blood cell, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width, platelet count, and platelet distribution width that can trigger anemia [14].

In addition to the high rate of anemia, the percentage of overweight in this study was also relatively high at 48.6%. This is similar to the situation in several studies among women workers in palm plantations, for example, Nurrachmawati et al. [15] found overweight prevalence at 43.0% in Kutai Kertanegara, East Kalimantan province while another study in Malaysia found 64.6% of women workers in their study as overweight [16]. Less diverse food with heavy intake on single carbohydrate source and sugar consumption was pointed out as the causes of the high rate of overweight in those studies. This might also apply to the subjects in this study.

Furthermore, women workers on palm plantations tended to have fewer working hours compared to other types of plantations (such as rubber or rice) and thus had more leisure time which was used more on sedentary and social activities [17]. This might add to the cause of the high rate of overweight. Additionally, low level of education of women workers in this study could also be a risk for high rates of overweight as suggested by Witkam et al. through a systematic literature review and meta-analysis which shows that a lower level of education is associated with obesity, especially for women [18]. Education were related to access to information, where an individual with higher education has greater access to information related to health and therefore, they were able to choose the healthier options [19].

Interestingly, the high percentage of overweight might be associated to the high rate of anemia. This was, for example, reported by Lipoeto et al. which shows a positive relationship between BMI and anemia [20]. Similar researches conducted by Saad and Qutob and Alshwaiyat et al. also show positive relationship between obesity and anemia [21, 22]. It was suggested that chronic inflammation in obese or overweight person would elevate a hormone called hepcidin, a peptide hormone that plays an important role in iron homeostasis [23] which in turn would decrease iron status. Hepcidin interferes with iron absorption and was found to be at a higher level among obese and overweight people compared to normal weight people. It should be noted that anemic or not, obese and overweight people are more likely to be iron deficient compared to normal weight people [21].

Earlier, it was reported that iron deficiency prevalence among obese adults was higher than that among non-obese adults, in which Yanoff et al. labeled this situation as obesity hypoferremia (literally meaning low iron serum) [24]. In addition, NHANES III data shows that overweight children were more likely to be iron deficient than normal weight children [25].

However, studies indicated that iron supplementation among obese and overweight persons would not be as effective compared to normal weight people [22, 26]. Again, in this case, increased hepcidin levels played a role in reducing iron absorption [22]. This implies to the anemia reduction program. To be effective, iron supplementation should be accompanied by increasing physical exercise to those with overweight and obese problem. Teng et al., reviewed that energy-restricted diet and/or exercise would improve obesity hypoferremia and iron homeostasis among those with overweight or obesity [27]. In addition, Coimbra et al., showed that an 8-month exercise program could decrease inflammation and hepcidin levels, and increase serum iron concentration [28].

One limitation of this study was a relatively small number of respondents, especially to enable further analysis to separate association analysis among different group of overweight and anemia status. This analysis would be useful to confirm different types of anemia, whether it is overweight related or more dietary deficiency or both. Another limitation is related to iron deficiency status which is only reflected in hemoglobin level and not on other markers of iron deficiency. However, it is hoped that this research will trigger future researchers to conduct research on anemia in women workers on oil palm plantations with a larger number of samples and using other means of examining anemia such as iron tests and reticulocyte count tests.

This research used a cross-sectional design to determine the prevalence of anemia and the determinants of anemia in women workers on oil palm plantations. This design certainly has weaknesses, including its inability to determine causal relationship, however, as a preliminary study in this area, the design was the most feasible one. Moreover, results of the analysis were considered useful for providing early evidence to be followed up in future studies with a more robust design. Future researchers can further examine the relationship between iron, vitamin C, calcium and the physical environment with anemia status in female workers in oil palm plantations by using other designs, such as clinical or community trial.

Conclusion

This study observed a high prevalence of anemia among women workers in palm plantations in the study area. This might also be related to high overweight prevalence which indicate a more complex situation of anemia condition among women workers in palm plantations. Low iron intake (OR 13.5), low vitamin C intake (OR 4.6), high calcium intake (OR 0.02), multiparity (OR 3.4), and poor physical environment condition (OR 2.8) were all significantly related to a higher risk of anemia. Various causes of anemia should be considered in intervention or supplementation programs.

A combination of nutrition and other health intervention including systematic surveillance would be suggested not only to alleviate but also to prevent the problem. Both government and companies should take curative, preventive and promotive action to eradicate anemia among women workers in palm plantations. All parties (company, government, academia) should collaborate to develop effective nutrition and reproductive health education program targeted toward plantation workers. Existing program such as Healthy Productive Female Workers/Labor Movement) could be utilized to monitor the problem of anemia and to enhance program deliveries.

Future study in palm plantation workers would be suggested to include a larger number of respondents as well as the use of variety of study design including both qualitative and quantitative approaches or mixed methods to gather a more comprehensive information regarding nutrition and health of plantation workers.