Malnutrition is a major public health problem leading to child morbidity and an underlying cause for more than half of child deaths worldwide, particularly in low socioeconomic communities in developing countries [1, 2]. Insufficient dietary consumption and infectious diseases are major contributing factors for poor nutritional status of children [3, 4]. Young children are more prone to malnutrition because of high protein and energy needs and vulnerability of infections than adults [5]. Undernourished children are less productive of physical and mental development and increase susceptibility to infections and the risk of early deaths [6–8]. Malnutrition commonly has long lasting effects among children and adversely influences their adult logical and work capacity [9]. Anthropometric measurements are a cost-effective and reliable method to evaluate the health and nutrition status of the individuals and in a society [10]. To identify the actual priorities of child health within a society, it is necessary to determine the associations between individual variables and health-related factors in a child population.

Previous studies in Sri Lanka reported that undernutrition among children is still a major health problem associated with poor sanitation and personal hygiene, low socioeconomic status, overcrowding and low educated parents [11–14]. The plantation system was introduced by the British governors around the mid of the nineteenth century with tea and rubber. They brought Tamil community from South India to Sri Lanka for the purpose of working as laborers in the plantation sector and they now comprise about 5 % of the total population in Sri Lanka [15]. One of the major features of the plantation sector is laborers residing and working in the same plantations for generations. Therefore, Tamil community in the plantation sector has been isolated socio-economically and geographically from the other parts of Sri Lanka. In the twenty-first century, plantation community showed the lowest educational levels, health and nutrition conditions and the highest mortality levels in Sri Lanka [16].

The demographic and Health Survey (DHS) in 2006 reported that 30% of children less than 5 years in the plantation sector of Sri Lanka were underweight (< −2SD weight-for-age), 42% were stunted (< −2SD height-for-age) and 13% were wasted (< −2SD BMI-for-age) [17]. The Literacy rate in the plantation sector of Sri Lanka was 86.1%, while the national average was 95.7% [17]. Infant mortality and low birth weight (less than 2.5 kg) in the plantation sector were 29% and 31%, respectively, while the rates of Urban and Rural sectors were less than 20% [17]. Access to safe water in the plantation sector is 52.4% and the corresponding percentages for Urban and Rural sectors were 98.9% and 90.9% respectively [18]. Nearly 73% of households in the plantation sector had latrine facilities while the national average was 86.7% in 2012 [18]. It is important to determine the true extent and underlying causes of child nutritional status in the plantation sector of Sri Lanka to commence proper intervention strategies to decrease the levels of malnutrition in childhood. However, limited data are available on nutritional status of children and its association with socio-economic characteristics in the plantation sector. Therefore, this study was designed to determine socio-economic characteristics associated with the nutritional status of children in the plantation sector, Sri Lanka.

Malnutrition causes children more susceptible to infections. Those frequent infections negatively affect their physical and cognitive abilities locking them into a vicious cycle. This study confirms that undernutrition is still a considerable health problem in the plantation sector in Sri Lanka. This is much similar to the prevalence of malnutrition reported by the DHS of Sri Lanka in 2006 [17]. However, National Nutrition and Micronutrient Survey in Sri Lanka reported that 15.1%, 27.3% and 21.9% of children aged between 6 and 59 months had stunting, underweight and wasting respectively in 2012 [20]. It is commonly believed that these differences result from a low standard of living, high levels of infectious diseases, and low purchasing ability, all of which have an effect on feeding practices [21].

In the present study, primary school children are more likely to be undernourished than preschool and secondary school children. Preschool children, mainly depend on breastfeeding and may be protected by the mother’s immune system at birth [22]. Breast milk protects small children from infectious diseases and finally affects their nutritional status. With the increasing of age, children start to take complementary food in addition to breastfeeding and get nutrition from many food sources. Some studies have reported that the deviation of normal growth rates in children starts from several months after birth because breastfeeding is no longer enough to fulfill the requirements of growing children [23]. Inadequate complementary foods also might be a reason of increasing trends of malnutrition in older children. This might be attributed by stopping or reducing breastfeeding and insufficient intake of complementary food.

Underweight was the most common undernutrition indicator among these children. WAZ reflects body mass relative to age and it fluctuates with time and therefore it has a role in acute as well as chronic malnutrition [24]. High prevalence of stunting and wasting also reveal that most of the children in the study groups were suffering from long term chronic malnutrition, which negatively effect on both mental and physical improvements in childhood. Decreasing food purchasing ability, dietary changes and poor personal hygiene of mothers as well as infectious diseases may have a role in the nutritional status of children [21]. The present study revealed that primary school children showed the lowest mean Z scores of WAZ and HAZ compare to preschool and secondary school children. Since undernutrition increases with age, it reflects longer exposure to chronic malnutrition is common among children in this community. Knowledge of food nutrients and improved hygiene are a few of the factors that could be involved in reducing the prevalence of undernutrition among secondary school children.

Social customs and norms in communities and families describe the roles of members in households. In Asia, a number of the restriction process consists regarding the health of small children [25]. This study showed that preschool female children had significantly higher rates of underweight and stunting than male in this community. This is inconsistent with the studies in India and Bangladesh reported that moderate and severe undernutrition was higher in female [26, 27]. Gender inequality of male preference over female in care and feeding practices could be a major reason for this finding and it is commonly seen in many cultures and social beliefs in Asia [28]. In addition, Religious influences also discourage the consumption of some healthy foods. Therefore, child feeding practices of mothers and caregivers may affect dietary intake of children in this community. This indicates that more attention on the maternal characteristics at the household level should be paid for the improvement of child health particularly in preschool stage.

Education generates knowledge and favorable environment that positively affects for child health. In the present study, a declined trend of child malnutrition is observed where the educational level of mothers increased. Similar findings were reported in numerous studies showing children with low educated mothers had higher prevalence of undernutrition than highly educated mothers [29–32]. Education makes the mothers inform nutritional values of food and get more understandings of child physical and mental growth. Underage marriages are still common in the plantation sector and most of young low educated, married girls are neither mentally nor physically ready for motherhood. They often have a greater chance of giving low birth weights children [33]. This could be another factor for child undernutrition in the plantation sector. National Family Health Survey in India revealed that underage marriage mothers were a contributing factor for undernutrition of their children [34].

The main source of income for most families in these communities is working as laborers in tea plantations on a day-to-day basis. Because of the uncertainty in these occupations, both parents prefer to work in the industrial sector or migrate to Middle Eastern countries. Therefore, parents, particularly mothers have very limited time to prepare meals and feed children at home. Most of the children in the plantation sector spend their day time with grandparents or other relatives and this could be disadvantaged on children’s physical and mental growth and development particularly in preschool and primary school children [33]. Children of unemployed mothers were better nourished than the children whose mothers were employed [35, 36]. In addition, employment of mothers outside of their homes creates many social problems in family level and it negatively affect for the physical and mental development of children [37]. In many cultures in Asia, father is the money earner and the decision maker at the household level. Highly educated fathers more care of their children and provide health facilities when they need. However, in this study, high educated and occupied fathers play a significant role in decreasing the rate of wasting among secondary school children. This could be an ability to make decisions about getting good quality food for children [38, 39]. Further studies are needed to determine how parents’ educational influences to the nutritional status of children.

Generally the majority of residents in the plantation sector live in the same places where their previous generations were lodged called “Line houses” without major modifications. In this community, 68% children lived in long terraces of one or two room houses attached to each other under minimal socio-economic conditions. Further, few subjects were living in quarters and detached houses. The high prevalence rate of underweight among children in attached houses indicates that poverty and poor sanitary conditions were common in this study group. Similarly, a survey in India found that the prevalence of undernutrition among children in low standard households increases two times than the children living in high standard households [40]. In the present study, we revealed that sanitary and treated water facilities were inadequate in this community. This causes the high prevalence of repeated infectious diseases still remain in the plantation sector [11–13, 41–43]. Inadequate dietary intake weakens the responses of the immune system in children and increases vulnerability to infections. Several studies have been confirmed that infections were commonly diagnosed in children suffering from undernutrition [44, 45]. Another study identified that soil of the plantation sector of Sri Lanka has been contaminated with helminth eggs [46]. When handling contaminated soil, water or food those infective stages of micro-organisms can enter into the body and initiate diseases. This association between undernutrition and infection generates a cycle of repeated illness and deteriorating nutritional status. Critical nutrition specific interventions include promoting micronutrient supplementation, breastfeeding practices, access to clean drinking water and good sanitation practices and reducing the incidence of underage marriage of girls and delivering children with low birth weights can break this cycle and enhance their nutrition status [47, 48]. Although, hospitals and dispensaries in the plantation sector provide basic medical services to the estate inhabitants, lack of qualified health staffs and medical facilities are the major difficulties faced by the health service in the plantation sector [49].

In the present study, majority of undernourished children has more than five family members. Poor allocation of household resources cannot fulfill the nutritional requirements of each member equally. Particularly, children in large family size have poor access to sufficient and quality food [50]. This is consistent with several studies in India that have identified that the large family size negatively affect for child nutritional status [51, 52]. In addition, the presence of many siblings is also a risk factor for undrenutrition due to limited availability of time for care and feeding of each child [53]. Another study has reported that the food availability of children in large families were lower than the children in small families [54]. Birth order affects the attention of mothers to intra household activities and child care. In the present study, higher birth order has a negative impact on wasting in preschool children. This reflects the nutritional status of the first children to be better than that of last children. However, in the wide confidence interval (CI = 1.23–33.08) means that the data on wasting are too inconstant to make a reliable estimate. Families with more children have a high economic burden for the consumption of food and thus majority of young children are likely to be undernutrition [47]. Similarly, children in higher birth order (>3) were prone to undernutrition than those with low birth order in India [55]. Family planning programs promoting the reduction of the size and increasing the gap between childbirths will reduce the numbers of malnourished children from higher birth rates.

More than half of children use common latrine facilities in this community and shows a higher prevalence of underweight than those used household latrines. This might be explained by the poverty and lack of good quality latrines. Similarly, several studies have revealed a large number (>50%) of children living in tea plantations in Sri Lanka used poorly defined public toilets and open ground for their defecation [11–13]. Water purification centers were not available in this area and water from unprotected storage tanks were used for domestic requirements (i.e., drinking and washing clothes). Studies conducted in Sudan and Philippines revealed that improved water and better quality sanitation facilities positively affect, for good health conditions of children [56, 57]. Some studies have been reported that untreated water causes diarrheal diseases and positively correlated with the malnutrition of children [58, 59]. Therefore, we suggest that sanitary facilities affect the nutritional growth irrespectively of social demographic characteristics.

High household income of the family offers the opportunity to provide good quality food and more health services. Another study shows the links paternal education is a strong determinant for enhancing the household income in developing countries [60]. Household Income and Expenditure Survey in 2012/2013 reported that mean income per household in the estate sector were 30,220 (USD 201) Sri Lankan Rupees (SLR) while the national level was SLR 45878 (USD 305). However the majority of this community had less than 20,000 rupees (USD 133) per month income [18]. In this study, Underweight was more common in lower income groups than children in higher income households. This is similar to the studies conducted in India showed that children in low income groups had a high rate of undrenutrition [61]. This indicates that poverty is not the only factor responsible for undernutrition but inadequate dietary intake, infection, poor hygienic habits and the environment and low education status might contribute to child undernutrition among low income groups. Access to higher education for women and family planning programs, improvement of sanitary facilities and the socioeconomic conditions are major factors to enhance the child nutritional status of this community. However, an obvious limitation is this study was not powered for many of the comparison made and it was only powered to estimate an overall prevalence for all children 1–15 years old.

Parents’ education and occupation, birth order, number of siblings, family income and gender are main attributes to the undernutrition in this community. Government as well as non-government organizations need to prioritize to implement community based programs to enhance the knowledge of child health and decrease the level of undernutrition. In addition, future detailed studies are required to determine factors affecting the nutritional status of children in this study area.