This paper documents socioeconomic and nutrition characteristics of two areas of informal settlements in Nairobi, Kenya. Even though Dagoretti’s deprived areas are urban by definition, they have a peri-urban character, with lower population density and more agriculture activities, than Korogocho, which is a shanty-town inside the city. The levels of malnutrition and risk of inadequate intakes were high, highlighting that pockets of malnutrition exist in poor urban areas of Nairobi. Nevertheless, the women and children residing in Dagoretti clearly showed better socioeconomic and nutrition status than in Korogocho, and so might be a better model for informal development. The data show that even among low-income households in Nairobi there can be a wide range of variability and hence the importance of stratifying data in urban areas in research and policy design. Some socioeconomic indicators, including livestock ownership, were found to be associated with nutritional outcomes, which is of relevance for policy and intervention design.
The data (income and family size) indicate that majority of households, in this study live under the World Bank international poverty line set at 1.25$ per day per person . Female-headed households had significantly lower incomes than male-headed households; whereas they were similar comparing other socioeconomic indicators. These results may reflect a misclassification bias. We could not distinguish between female headed households with an absent male-head versus those with no male head. The first named might receive financial support from a husband living away, which could attenuate differences between female and male headed households.
The quality of housing was mostly classified as ‘Poor’ (i.e. scores ≤10), with only a few households being ‘Average’ (i.e. scores between 11 and 20). All indicators related to ownership of land, domestic assets and animals were better in Dagoretti. Gender disaggregation of asset ownership including livestock is important to identify gender disparities and track potential inequity reduction resulting from targeted interventions. Ownership of assets by women increases the decision power and thus has been associated with positive outcomes in health and education . Assets like livestock can have specific impacts on food access and availability [41, 42]. The median gender asset disparity was 0.7, relatively high, indicating female ownership was important. This could be due to the relative presence in the sample of female-headed households (one in four households). In addition, the concept of ‘ownership’ of assets might need further exploration. For example, respondents might say that assets belong to the household and thus to all of its members, but this might not be the case when a couple divorces. In such situations gender disparity could raise, with women losing important assets. A different question formulation could be investigated in this respect in further studies, to obtain more accurate information and assess capacity of women to respond to ‘household internal shocks’ .
In this study, 29.3 % of households owned livestock, which is comparable to other African urban settings . Animals are particularly important assets, contributing in multiple ways to household economy, in particular to either income generation and/or the household’s own food consumption [44, 45]. The number of heads and species owned can be highly informative to the household’s socioeconomic characterisation, and be strongly related to productivity, income and welfare in some rural settings of developing countries. While in rural areas the majority of household keep livestock, the less well-off are more likely to keep livestock . In urban areas livestock ownership is generally less common due to space and other restrictions, but the same trend seems to apply . However, these trends can also be context-specific, and African countries such as Malawi or Tanzania have shown that rural wealthier households were likely to own more livestock [44, 46]. The households keeping livestock in Dagoretti (and an animal biomass (TLH) more than double that of Korogocho) might contribute to a diverse livelihood portfolio, and improve resilience, and dietary quality. However animal concentration can also increase the zoonotic pathogen load in the household. In this study, income was positively associated with animal ownership; this increased income could be either the result of the small-scale livestock production and/or the reason for investment in livestock. Importantly, livestock was reported to be owned predominantly by the household (i.e. not by male members), and also sometimes by women. This deviates from findings in rural poor settlements and may be due to urban context where men can often have a job outside the household and are less involved in livestock. Again there can be differences in the understanding of the term ‘ownership’, since other work in Dagoretti (among richer dairy households) quoted people as saying “everything with blood in the house belongs to the man”, while finding that women dominated decisions about cattle milk, manure and the day-to-day care of cattle . The absence of refrigerators in both areas could pose a challenge to food preservation and food safety, particularly for foods of animal origin (i.e. meat, milk).
Maternal and child nutrition
The areas under study, like other urban low-income ones, showed the presence of a double burden of malnutrition in which high levels of chronic malnutrition (stunting) co-exist with high levels of maternal over-weight/obesity . In this study, 4 in 10 children between 1 and 3 years were stunted and almost one third of their mothers were overweight or obese . Anaemia was also an issue of concern, especially among children, and almost all non-breastfed children were at risk of inadequate iron intakes. The quality of diets was low. Over 50 % of non-breastfed children were at risk of inadequate intakes of iron and calcium; and over 50 % mothers were at risk of inadequate intakes of calcium, zinc, riboflavin and niacin. These nutritional profiles suggest that micronutrient-dense food must be promoted, rather than calorie dense foods, to prevent stunting and reduce overnutrition and its related diseases such as diabetes type II or heart disease. These chronic diseases are becoming prevalent in urban poor settings ; and will place an economic burden on health care systems, which might well justify a resource investment in the food production system and in education. Interventions at the food system level may contribute to economic activity as well as prevent long-term reduction in human welfare. Low intakes of essential micronutrients and high rates of stunting and child anaemia justify the promotion of nutrient-dense foods such as animal-source foods. In follow-up research, some related issues were addressed to explore the economic and sociological drivers of animal-source food demand, including price elasticities (Cornelsen L, Dominguez-Salas P, et al. Price and other drivers of demand for animal source foods in peri-urban Nairobi, Kenya. Forthcoming. 2016). These studies also analysed the characteristics of the Nairobi livestock value chains supplying these low-income dwellers, in order to assess associated limitations, challenges, upgrading opportunities and risks (Alarcon P, Fèvre EM, et al. Mapping of the beef, sheep and goat source food systems in Nairobi associated to markets and large processing companies. 2016. Forthcoming).
Prevalence of stunting above 40 % was ‘very high’ according to the WHO Classification for assessing severity of child malnutrition, and compared to national levels. This probably reflects long-term problems of food insecurity, poor diets and child feeding practices, micronutrient deficiency, infectious disease load and/or enteropathy, inadequate water and sanitation, among others [16, 17, 48]. Almost one in four children had recently been sick, which might be due to poor food and environmental hygiene and the effect of the rainy season. Malnutrition has consequences for the individual’s mental (cognitive) and psychomotor development, and the high prevalence of stunting observed in this study is expected to have serious long-term impact on the development and wellbeing of the Kenyan society as a whole. Tackling stunting in these settings can be challenging, but fostering prevention strategies must be a high priority. Conversely a ‘low’ level of wasting (<5 %) was found, which suggests dietary energy intakes were adequate. We observed a sex difference in the prevalence of stunting; however, this was not supported by differential intake in our data. A comparative advantage in girls has been reported in other studies and the reasons could be both biological (response to environmental stress) and cultural (differential access to food, care, or physical activities) [13, 49, 50]. Also, the difference in prevalence between Dagoretti and Korogocho could be related to differences in the general sanitation, population density, and environmental conditions between these two areas. The number of wasted children was not high, but our data showed coexistence of wasting and stunting and an association between them. Both conditions are associated with increased mortality, especially when they co-exist, and infectious diseases contribute to both of them, as do inflammation and gut health (via the effects of chronic inflammation, malabsorption and/or appetite effects) [51–53]. There is also evidence that weight and length at birth determine later linear (and potentially ponderal) growth, and therefore women should be targeted via maternal (and pre-maternal) health and nutrition support. In children below five years, stunting, severe wasting and intrauterine growth restriction together are estimated to contribute 21 % of total global disability-adjusted life-years (DALYs), which constitutes the largest risk factor in this group . Child anaemia prevalence was above the 40 % WHO anaemia threshold considered as a ‘severe public health problem’ , and does not seem to have improved from data from the latest comprehensive survey on anaemia prevalence in 1999, which was 69.0 % for preschool-age children countrywide .
Breastfeeding practices recorded were better than previously reported for these settings ; however, the follow up methodology in that study was different: focusing on younger children and with feeding practices being longitudinally recorded in detail. The nutrient intake of children surveyed in Korogocho was consistently lower than those in Dagoretti for all nutrients and child groups, but was only statistically significant in non-breastfeeding children (with the exception of vitamins A, B12 and C), probably due to the relative sample sizes. B12 was abnormally high in this population probably due to the national mandatory fortification of refined maize flour for the key staple ‘ugali’. An increased blood level of vitamin B12 due to high intake is unlikely, as only small amounts of vitamin B12 can be absorbed and the rest is removed in the urine. Therefore, no tolerable upper intake level (UL) has been set . Doses as high as 2000 μg have not shown significant side effects . Lower intakes in Korogocho could be due to lower income among the households, although anecdotal observation indicates that food prices are also lower in Korogocho. Also, the access to nutrient-rich value chains could differ among areas. The minimum dietary diversity score was high in Dagoretti compared to studies from other sub-Saharan countries, probably due to the urban nature of the population [58, 59], but was significantly lower in Korogocho. In these settings, there is a need to assess if the right quantity and quality of food to ensure dietary requirements can be met with local diets, and thus enable children and women to reach their optimal weight, heights and cognitive capacity. The lack of association between the individual haemoglobin levels and iron intakes might be due to the absence of repeated day intake measurement and inherent measurement error associated with estimating dietary intake, as well as other factors such as parasite infestation. Despite the existence of a programme distributing sprinkles to children under 5, no household reported consumption of sprinkles within the 24-h recall.
The prevalence of 29.1 % overweight (9.9 % obese) in women was lower than previously reported in Korogocho and Viwandani from a sample of older women , and coexisted with 7.4 % of women being too thin. The key risk factors for obesity in these areas deserve further investigation and could be related to high intakes of carbohydrates and oil, and to lack of physical activity. The prevalence of anaemia in non-pregnant women was low compared to children but in line with the national prevalence in women of reproductive age (25 %) . Yet, it would still be classified as a ‘moderate public health problem’; also, Nairobi has low malaria prevalence. In any case, health policies on anaemia prevention and control introduced by the Ministry of Health over recent years to address the high rates of anaemia need to be formally monitored and evaluated. Taking iron supplements during pregnancy was reported by almost half of the women, although the compliance period was relatively short. Night blindness was also lower than the 6.8 % reported in the 2008/09 demographic and health survey  although it is not fully comparable since that study referred to both sexes and to different areas. This was in turn higher than the 4.3 % found in that same survey for rural populations, indicating that dwellers of poor urban areas could have a more limited access to vitamin A rich foods. Nutrient intakes were consistently lower for all nutrients except for vitamin B12 and iron in Korogocho women than in Dagoretti ones, but these differences were only significant for calcium, zinc, riboflavin, vitamin B6 and folate. The significantly higher intake of calcium and riboflavin in Dagoretti could be due to higher fresh milk intakes in this area, possibly facilitated by a higher presence of livestock. Women’s dietary diversity indicators were also lower in Korogocho and were in line with previous findings . Ethnicity was not included in the questions to avoid potential sensitivity but it should be explored in the future since dietary practices and patterns have been observed to differ among ethnic groups . A double burden of malnutrition was identified among women, and better nutrition of the woman and child assessed seemed to be associated within households. In addition, higher weight may be related in this population to higher caloric intake from commonly used fried street foods such as ‘mandazi’ (a sort of doughnut) and oil, and not to good quality foods, thus not preventing stunting or anaemia.
Predictors of malnutrition
Some factors related to poverty have been identified in previous studies as associated with suboptimal nutrition . Among the sociocultural predictors explored, the best predictors of stunting in this study were lower education of the head of the household, sex of the child (with girls having lower stunting rates), and marital status (with married women having more stunted children). Lower education and not being married have been previously identified as risk factors for stunting  and breastfeeding cessation . Higher education is likely to be associated with higher knowledge, higher income and more positive health and nutrition practices. Surprisingly, contrary to the previous study, in this sample children of married women were more likely to present lower height-for-age than children of single or divorced women. Although this study includes a different setting (Dagoretti), with a different socioeconomic reality than Korogocho and Viwandani, this finding requires further investigation. Weight-for-height showed positive relationship with female livestock ownership expressed as number of tropical livestock units, suggesting a beneficial effect of women owning animals as regards wasting in these settings, although this association was only marginally significant and would require further study. Evidence so far has shown that animal ownership may relate to better nutrition at household level [45, 66–68]; this has been reported for stunting in rural populations, and the pathways are still unclear. The lack of association of stunting with animal assets in this sample might thus be due to different dynamics of animal use and expenditure patterns in these urban areas compared to rural ones. In poor urban settings, direct pathways contributing to own consumption of animal-source foods could be affected due to animals being kept far from households (in this sample, households with higher number of animals i.e. >5 heads of ruminants or >10 heads of poultry were kept mostly outside the urban area) and therefore contribution to daily intakes might be limited, or alternatively to fewer animals kept. Indirect pathways of income generation to purchase food might also be affected due to a higher number of competing priorities for money expenditure. In addition, animals in overcrowded areas could contribute more easily to zoonotic disease via environmental contamination, potentially contributing to malnutrition. Therefore, the interaction with animals in these settings could be substantially different to rural areas and deserves further investigation. The association found with wasting rather than with stunting could be due to the sale of animal-source foods to buy caloric foods (staples, oil, etc.) rather than for own consumption. The negative association of income with weight-for-height and maternal BMI was unexpected. It is important to note that the difference between income categories is limited, and households may have varied among income category each month, as incomes were often irregular. Again, this finding might be related to expenditure dynamics: when additional income was obtained in a month, it might have been diverted to other household needs, reducing intakes. The fact that it was not associated with longer-term indicators such as height-for-age is reasonable when income differences are not related to higher level of education or knowledge, as adequate height-for-age at young age does not only rely on sufficient quantity of intake but also on quality of diet and good weaning food practices. Anaemia was not strongly related to any of the factors, and the effect of other factors such as intestinal parasites might be more important. The lack of association of nutrition with domestic assets might be related to the choice of assets, whose ownership might not be meaningful enough in these settings as to characterise different types of households (for example, in an urban area certain assets such as second-hand radio or a cooker might be easier to obtain at an affordable price; so which might be the best indicators for this type of context deserves attention).
The households visited were relatively homogeneous in terms of socioeconomic parameters, and the range restriction might make it more difficult to establish differences. It must be noted that levels of acute malnutrition and BMI could substantially differ throughout the year, where different food availability, prices and access, and ultimately intake, as well as a different pattern of diseases are likely. Specifically, this study took place at the end of the short rainy season and weight could have been lower due to increased infections (respiratory infection, diarrhoea, etc., particularly in children) resulting, for example, from poor structures for water and sanitation and associated flooding. Also, as noted, part of the data was collected prior to Christmas festivities and part after, when purchase power may be lower. Although there was a two-week interruption to ensure a wash out period, weight might have been affected by festivities, when trips to rural areas are frequent (potentially with access to more diverse foods), as well as having relatives visiting for celebrations, and better meals and higher intakes. Data collection throughout the year would help obtain a better picture of the nutrition situation and capture seasonal variations. In any case, dietary data are subject to bias arising from recall, the error introduced by FCTs, and both respondent’s under-reporting and over-reporting, which are expected to balance out on average, but may be important at individual level. Also, more than one day of observation would have been preferable to capture the intra-individual variation. A specific difficulty in a setting where food is often sold in small repacked portions is the misclassification of certain foods (e.g. flour composition, oil type). Finally the limited sample size might have prevented detection of statistically significant small differences and association. The necessary division between breastfed and non-breastfed children reduced further the sample size in some of the child comparisons.