Effect of household socioeconomic status on disposable diaper use and disposal in Greater Accra, Ghana and Kisumu, Kenya: a cross-sectional study

Rapidly changing urban lifestyles in low- and -middle-income countries (LMICs) are increasing municipal waste generation, changing the composition of solid waste for disposal, and posing waste management challenges (Sharma & Jain 2020). As part of this broader trend, widespread consumption of disposable diapers (DD) has been reported by several local-scale studies (Miller-Petrie et al. 2016; Muia 2018; Nyamayedenga & Tsvere 2020) and a limited number of national market research surveys (Dey et al. 2016). The latter captures DD use but not disposal. Several studies have found mismanaged DD waste at illegal dump sites or scattered in the urban environment. For example, in urban Zimbabwe, Pakistan, and Thailand, disposal via illegal dumping of absorbent hygiene products, including DD, has been reported (Velasco Perez et al. 2020). Discarded DD, locally in high densities, was also identified in scattered waste during environmental transect surveys of slum neighbourhoods in Kisumu and Greater Accra (Umar et al. 2023). However, a review of DD disposal with solid waste (Reese et al. 2015) found a paucity of empirical studies of DD use and disposal in LMICs.

Studies in the USA suggest that DD may have convenience and time-saving benefits for children's carers (Massengale et al. 2017; Sadler et al. 2018). However, these benefits need to be balanced against the potential harm from the unsafe disposal of used DD. As complex composite products, DD comprise a cellulose pulp and polyester acquisition and distribution layer, an inner cellulose core encapsulating a superabsorbent polymer, a polypropylene top sheet, and a polyethylene back sheet (Velasco Perez et al. 2020). This complex composition poses significant challenges for waste management, meaning discarded DDs persist in the environment, do not burn easily, and are a source of plastic waste (Ntekpe et al. 2020). Inadequate DD disposal can also result in blockage of sanitation systems (Sommer et al. 2013) and storm drains (Salles et al. 2012) and may constitute a faecal contamination hazard, for instance, since human faeces in household compounds attracts flies (Islam et al. 2018), thereby exacerbating a pathogen transmission pathway. Additional transmission pathways include oral contact as young children play with DD waste or contaminated items; inadvertent pathogen transport by adults; groundwater transport of pathogens into shallow wells; and surface run-off washing pathogens from DD into water sources (Zerbo et al. 2022). Mismanaged DD waste also poses an occupational health risk for waste pickers (White et al. 2023). DD use may also affect toilet-training behaviours, with their increasing popularity implicated in a global trend towards a later toilet-training age (Blum et al. 2004), and a Turkish study found later age of toilet-training initiation among DD users (Koc et al. 2008).

By analysing nationally representative household expenditure surveys for Ghana, Nigeria, and Kenya, we recently identified widespread DD purchases among households lacking waste services (Thomas-Possee et al. 2024). Our study found that 26.7 and 47.8% of Kenyan and Nigerian households with young children purchased DD. Most lacked solid waste collection services, with waste burning predominant among this group in Ghana, but indiscriminate dumping predominant in Kenya and Nigeria. However, in our secondary data analysis, it was unclear whether DD purchases were systematically underestimated because of respondent survey fatigue or recall bias. Since these surveys only report the main method of household waste disposal, it was also unclear whether households disposed of used diapers with other solid waste or separated discarded DD for disposal by other means.

Highly varied policy responses to DD use have been proposed. These range from a complete ban (Malindi Kenya 2019), increased sales tax on diapers, and promotion of alternatives (notably reusable cloth diapers via social enterprises), to subsidised or free DD provision via diaper banks (Sadler et al. 2018). The latter was proposed by Kenya's President Ruto in 2022 for children under 3 months (Kathambi 2022). There is a related debate over the classification of child faeces disposal as solid waste (Bain & Luyendijk 2015) for international monitoring of Sustainable Development Goal Target 6.2. The United Nations Children's Fund/World Health Organization (UNICEF/WHO) Joint Monitoring Programme (JMP) originally considered child faeces disposal as safe when a child used a toilet facility of any form or its faeces was buried or placed in a latrine (Mugel et al. 2022). Subsequently, the JMP classified burial as unsafe because of potential transport by rain, groundwater, or animals (Bain & Luyendijk 2015). The JMP now considers child faeces disposal as appropriate where the child uses an improved sanitation facility (i.e. one that hygienically separates excreta from human contact) or its stools are rinsed into such a facility (WHO/UNICEF 2018). Stool disposal with solid waste is considered appropriate if waste is stored, collected, and disposed of by sanitary means, but a clearer definition of sanitary waste management is needed (Bain & Luyendijk 2015). Empirical evidence on diaper consumption and disposal is thus needed to inform policy.

Our study, therefore, aims to provide evidence to inform policy concerning DD by addressing the following questions in two case study LMIC cities:

• How does household socio-economic status affect DD consumption and use?

• To what extent are used DDs disposed of appropriately?

• What do children's carers perceive as the benefits of DDs?

In addressing these questions, our study also aims to corroborate household consumption behaviours and assumptions underlying our national-scale analysis of DD consumption (Thomas-Possee et al. 2024). We hypothesise in this study that women in poorer households ration DD use, sometimes reusing DD after child urination. We also hypothesise that their use is widespread in this group but that the group faces challenges with the safe disposal of used DD.

This cross-sectional study comprised a questionnaire survey of children's carers attending a sample of health facilities for child health clinics. The study took place in the cities of Greater Accra, Ghana, and Kisumu, Kenya. Greater Accra and Kisumu provide contrasting case studies for DD use and disposal since Kisumu has much lower solid waste collection (18%) and sewered sanitation coverage (19.2%) than Greater Accra (68% and 50.8%, respectively) (Kenya National Bureau of Statistics 2019; Ghana Statistical Services 2022). In Kisumu, the private sector undertakes most waste collection weekly or monthly, which cost households KSh100-500 in 2017 (US$0.96–$4.80) (Sibanda et al. 2017). Greater Accra's privatised municipal waste service providers collect waste weekly or monthly for most of the city, charging households $4–$12 in 2019 (Oduro-Appiah et al. 2019). As a capital city with a population of 5 million in 2021 (Ghana Statistical Services 2021), we further hypothesised that Accra's DD retail chain would be more developed than that of the regional city of Kisumu with its population of 398,000 in 2019 (Capuano Mascarenhas et al. 2021). Accra is home to a DD manufacturing plant, established in 2018 (Yi 2018), whereas the equivalent plant in Kenya is in Nairobi County, not Kisumu (Xia 2021). Kenya and Ghana also have contrasting national waste management policies, since Kenya has banned plastic carrier bags (Behuria 2021), replacing these with woven or biodegradable reusable bags known as ‘uhuru’ bags. In Ghana, there is no such ban and urban consumption of sachet water (water sold in 500 mL plastic bags) is widespread (Stoler et al. 2012).

Participants were adult carers of children aged 0–36 months attending vaccination clinics at selected health facilities. About 82.3% of children aged 12–23 months in Greater Accra had received all basic vaccinations and just 1.2% had received no vaccinations in 2014 (Ghana Statistical Services et al. 2015). In Nyanza Province, Kenya (which contains Kisumu), the equivalent figures in 2014 were 77.2 and 1.0%, respectively (Kenya National Bureau of Statistics, Ministry of Health, Kenya, National AIDS Control Council, Kenya, Kenya Medical Research Institute, National Council For Population and Development/Kenya 2015). Thus, sampling children at health facilities captured DD use among the majority, who vaccinated their children. In Kisumu, we lacked a health facility list to use as a sampling frame. We therefore purposively selected two public and two private health facilities offering child vaccination clinics, with one of each pair of facilities serving populations of low or medium socio-economic status and high socio-economic status, respectively. In Greater Accra, two private facilities were randomly selected (see Supplemental Figure S1), alongside two public health facilities, with one of each assessed by the research team as serving either low/middle-income or higher-income catchment populations.

Although there is minimal data on DD use in Africa, market research data suggests that the mean daily DD use per child in 2007–2008 was 2.3 in the Philippines, 0.3 in India, and from 5.6 to 4.1 DD/child/day in the USA (Dey et al. 2016). Based on knowledge of childcare behaviours in both cities and market research data from other LMICs (Dey et al. 2016), we assumed nappy use of 4 DD/child/day among high socio-economic status households versus 2.5 DD/child/day among medium or low socio-economic status households. Assuming a standard deviation of 2 nappies/child/day and sampling of two equally sized groups of low- and high-income households, we conducted a power calculation to test for a difference in mean nappy use per day by socio-economic status. This suggests a sample size of 39 in each 12-month age and income group would enable us to detect differences in DD use by income group with 90% power, which was rounded to 40. This gave a desired sample size of 240 children's carers in each city, combining all age cohorts. We used quota sampling to recruit the required number of children in each 12-month age cohort.

Following seeking their informed written consent, we surveyed carers of young children attending child health clinics between 20th March and 21st October 2023 in Kisumu and 20th March and 27th August 2023 in Greater Accra. The survey team asked children's carers about their age, level of education, housing characteristics, and economic activity. They also asked for the attending child's age and sex. Interviews took place in Dholuo or English in Kisumu and Twi, Ga, Ewe, or English in Greater Accra, depending on the languages spoken by the respondent and interviewer. Interviewees were then asked about the socio-economic characteristics of their household; current child faeces disposal methods and reasons for these; weekly frequency and quantity of diaper purchases in the past week and usual quantity used/disposed of daily; and reason for facility attendance. Two questions concerned child faeces disposal and DD use. These were ‘Does your child wear a diaper (nappy)?’ and the multiple-response question ‘What do you use to collect urine or faeces from the baby/child who is with you today?’ Respondents were thus asked questions concerning the specific child attending the clinic. Interviews comprised a maximum of 38 questions and lasted approximately 15 min, with responses recorded using SurveyCTO software on a tablet (Dobility Inc. 2021).

Initially, the socio-demographic characteristics of respondents were compared to recent census statistics for each city to assess the representativeness of respondents sampled via this approach. A simplified version of the wealth index used in Demographic and Health Surveys (Rutstein & Johnson 2004) was then generated for each respondent. This index was constructed from the first component of a principal components analysis of dichotomous variables representing assets owned (house, TV, and car), having an improved water source on-premises, improved sanitation, being engaged in economic activity or retired, and having attended secondary education or higher.

To evaluate consistency in responses to questions concerning DD consumption, linear regression was used to test whether absolute differences between reported numbers of DD purchased versus used were greater when the respondent was not the child's main carer. The reported number of DDs purchased weekly had much greater variance than the reported number used daily (reflecting bulk purchases), so the latter was used in subsequent regression modelling. Bivariate and multivariate Poisson regression in Stata (StataCorp 2019) was used to examine the relationship between the reported number of diapers used per day and child age, gender, household wealth quintile, and a child attending a health facility because of ill health. Preliminary assessment of distributions and post-estimation goodness of fit tests confirmed the reported number of DD used followed a Poisson distribution. Since studies report that unimproved sanitation (Beardsley et al. 2024) and open defaecation (Beardsley et al. 2021) increase the odds of unsafe child faeces disposal, we also examined sanitation facility types in relation to the number of DD used. Sanitation access was examined via a separate Poisson regression model from the household wealth quintile, given that sanitation was incorporated into the household wealth index. The number of DD used in the first 36 months of a child's life was then estimated from the median reported daily DD use by yearly age cohort and wealth quintile. We used locally weighted regression (Cleveland 1979) of child age on toilet-training status to estimate the age when toilet training was completed. Bulk versus single diaper purchases were cross-tabulated against the wealth quintile to assess the extent of consumption-smoothing, whereby poorer households purchase goods in small quantities to manage their finances (Morduch 1995).

We tabulated reasons for DD use and DD waste disposal method, including whether there were separate disposal methods for DD versus mixed waste. Disposal through a collection service or at a public dump was considered adequate. DD disposal by indiscriminate dumping, dumping into pit latrines or septic tanks, and burning or burial were classed as inadequate.

In both cities, all children's carers who were approached participated in the study. However, it proved difficult to recruit older children in Greater Accra, since far fewer attended for treatment than in Kisumu. Thus, given recruitment issues in Greater Accra, the quota for older children aged 24–36 months was reduced to 40, instead of 80, therefore resulting in 200 and 240 children aged <36 months being recruited in Accra-Ghana and Kisumu-Kenya, respectively (Table 1). Responses thus related to a somewhat older cohort of children in Kisumu than in Greater Accra (Table 1) but with a similar gender balance. Adult carer respondents were largely mothers of children attending healthcare facilities in both cities, with significantly more mothers accompanying children in Kisumu.

Table 2 compares respondent characteristics from our health facility survey to census-reported household characteristics for the general populations of Greater Accra and Kisumu. In both Greater Accra and Kisumu, households recruited into the facility survey had greater access to solid waste collection services and sewered sanitation than the cities' general population as reported via recent censuses (Table 2). In Greater Accra, a larger proportion of survey respondents used bottled water than in the general population, while in Kisumu, a greater proportion of survey respondents had water piped to their dwelling than the general population. In both cities, survey respondents were more frequently educated at the secondary or tertiary level than the general population.

Almost all respondents, 93.5% of Greater Accra respondents and 94.2% of Kisumu respondents, reported using DD (Table 3). In both cities, DD was more frequently used in combination with potties than with washable (reusable) diapers. In such cases, respondents reported using DD only in specific situations, such as when travelling, at night, or when the child was sick. Some respondents (9.6% in Kisumu and 22.1% in Greater Accra) reported reusing DD after defaecation or after the diaper had gained weight from absorbing child urine to prolong their use.

Locally weighted regression of age on the proportion of children reportedly toilet-trained suggested that 44.8% of children in Kisumu were fully toilet-trained by 36 months (Supplemental Figure S2). In contrast, in Greater Accra, 81.9% were fully toilet-trained by 36 months, with 50.1% toilet-trained by 31 months. There was evidence of significant consumption-smoothing among poor households (Supplementary Tables S1 and S2). 25.7 and 65.2%, respectively of the poorest households in Greater Accra and Kisumu purchased DD individually rather than in bulk, compared to none and 2.1% in the wealthiest quintile (chi = 39.4 and 57.2 and p < 0.001).

In outputs from unadjusted Poisson regression models predicting the reported number of DD used per day (Table 4), incidence rate ratios greater than 1 signify increased DD usage, while values lower than 1 indicate reduced DD usage. Reported DD use thus declined with child age but did not vary significantly by child gender. Households in the wealthiest three quintiles in Greater Accra and the wealthiest quintile in Kisumu reported using significantly more DD. Unadjusted models indicated significantly lower reported DD use among children attending health facilities because of illness. However, significantly more children aged 24–36 months (56.3% in Kisumu; 40.0% in Greater Accra) attended facilities because of ill health than younger children <12 months (16.1% in Kisumu; 1.25% in Greater Accra). Thus, this difference reflected lower DD use among older children and was not significant in multivariate models adjusting for child age. The relationship between DD use with child age and household wealth quintiles remained significant in adjusted models. A separate Poisson regression model was fitted against the sanitation facility type instead of the wealth quintile. In Greater Accra, the number of DD used was significantly lower among households using pit latrines and public sanitation facilities relative to those using flush toilets in an unadjusted model (incidence rate ratio (IRR) = 0.68, p = 0.02 and 0.76, p = 0.02 respectively) and public facilities in an adjusted model (IRR = 0.78, p = 0.04) (Supplementary Table S1). In Kisumu, the number of DD used was also significantly lower among households using pit latrines or public sanitation facilities relative to those using flush toilets in both unadjusted and adjusted models (IRR = 0.68 and 0.70, p < 0.001).

In Greater Accra, the total DD used in the first 36 months of a child's life varied from 2,800 DDs for the poorest quintile, to 3,269 for the middle quintile, and 4,099 for the wealthiest quintile (Supplementary Table S2). In Kisumu, equivalent figures were 1,714 DDs for the poorest quintile, 1,869 for the middle quintile, and 2876 DDs for the wealthiest quintile. Respondents reported paying a median of GHS1.55 ($0.13 using the exchange rate at the survey mid-point) per DD in Greater Accra and KSh17.5 ($0.12) in Kisumu.

In Kisumu, 69.5% of respondents reported having DD waste collected or taking it to a public dump. A total of 65 (28.8%) households reported disposing of DD separately from general waste in Kisumu. Typically, in such cases, the disposal mode for DD was safer than that for general waste. For example, 19 Kisumu respondents who burnt general waste either had used DD collected or took them to a public dump, with one noting a specific DD collection service operating and a second noting a separate DD collection bin. Two buried DD separately from other waste. However, 17 Kisumu respondents reported dumping DD in pit latrines or septic tanks (Figure 3(b)).

In Greater Accra, 165 (88.7%) respondents reported wrapping used DD in plastics before disposal. In Kisumu, 42.9% (97) of respondents reported wrapping used DD in plastics or ‘Uhuru’ bags and 5.3% (12) in paper. After disposing of diapers, 177 (95.2%) Greater Accra respondents reported washing their hands with soap, sanitiser, or baby wipes (in three cases, including in the poorest quintile). In Kisumu, 201 (88.9%) respondents reported washing their hands with soap or sanitiser.

Our study suggests that almost all households in Kisumu and Greater Accra use DD for children aged up to 3-years-old, including some who lack adequate solid waste disposal facilities. In contrast to the traditional view of sanitation service delivery comprising sewered wastewater systems or onsite sanitation systems such as pit latrines and septic tanks, this suggests widespread commodification of sanitation provision for young children. This confirms recent reports of widespread DD consumption in several LMIC cities (White et al. 2023). Alongside the growth in the consumption of food away from home, extensive consumption of packaged water (sold in plastic bags or bottles) has been observed in some countries in West Africa (Wardrop et al. 2017) and Southeast Asia. In our study population, 88.5% of Greater Accra respondents reported using sachet or bottled water (Table 2), reflecting this trend. Taken together, widespread packaged water and DD consumption could be seen as an emerging form of private sector engagement with urban water and sanitation provision.

Our study suggests that poorer households in Greater Accra and Kisumu use less than 3,000 individual DD from birth to 36 months, thereby using fewer DD than populations in high-income countries and lessening related environmental impacts. For example, life cycle assessment studies have variously assumed 4,200 (Khoo et al. 2019), 3,799 (Aumonier et al. 2008), and 4,623 (Weisbrod & Van Hoof 2012) used over a child's initial years in high-income countries. This city-scale survey also suggests that most children in Accra and Kisumu have been toilet-trained by 31 and shortly after 36 months, respectively, following a global trend towards later toilet training (Blum et al. 2004). For example, a study in the 1950s (Brazelton 1962) found children had completed toilet training by 28.5 months, whereas more recent studies (Schum et al. 2001) found only 40–60% of children had completed toilet training by 36 months. Later toilet training among households lacking waste collection services would increase DD disposal challenges.

However, in Kisumu, our survey found that 30.5% of households struggled to dispose of used DD safely. These households burnt, buried, or dumped used DD, either in the environment or in latrines. There are fewer of these households in Greater Accra (Figure 3), where waste collection service coverage is higher. In Kenya, this confirms a recent United Nations Environment Programme plastic waste hot-spotting report, which suggested that nearly 2,000 tonnes of baby diapers leaked into the environment in 2018 in Kenya (IUCN-EA-QUANTIS 2020). DD was identified as the fifth highest plastic product leaking into the environment in absolute terms and the third highest as a proportion of consumption (IUCN-EA-QUANTIS 2020). A minority of respondents reported dumping DD into pit latrines or septic tanks, a behaviour reported elsewhere in urban Africa (Chaggu et al. 2002; Nakagiri et al. 2015). Although the JMP considers putting child stools into improved pit latrines an appropriate disposal mode (WHO/UNICEF 2018), adding solid waste (i.e. DDs) can impair onsite sanitation functioning (Buckley et al. 2008). However, small pockets of Kisumu households have access to separate collection bins and services for used DD, suggesting that this issue could be addressed by scaling up such small-scale DD separation and disposal initiatives.

In both Greater Accra and Kisumu, across all wealth quintiles, children's carers valued the convenience of diapers and perceived them as more hygienic for their children (Figure 4). These reasons for DD use mirror those cited in high-income countries, such as Canada (Shanon et al. 1990). Even poor households lacking on-premises water access seldom cited the reduced need for washing water as a reason for using DD over cloth diapers, so poor water access did not seem a significant driver of DD consumption. In the USA, beneficiaries participating in a mixed-methods study evaluating community-based diaper banks reported improved parental well-being, increased childcare and work opportunities, and the ability to divert household finance to meet other basic needs (Massengale et al. 2017; Sadler et al. 2018). Thus, there are likely benefits for children's carers in both cities from DDs that should be balanced against the harm arising from mismanaged DD disposal. This balance of benefit versus harm for DD is analogous to the protection from faecally contaminated water afforded by packaged water (sold in plastic bottles or bags) (Williams et al. 2015) versus the adverse consequences of mismanaged sachet or bottled water packaging waste (Wardrop et al. 2017).

The estimated prevalence of DD use in our study is higher than in many other Sub-Saharan African studies, likely reflecting the urban, comparatively wealthy population that we sampled. In Kenya, our national-level study found that 20.6% of rural and urban households reported DD purchases in 2015–2016 (Thomas-Possee et al. 2024). However, smaller-scale urban Kenyan studies have reported 86.2% of households in Nairobi County (Muia 2018) and 94.6% in Nakuru using DD (Wambui et al. 2015). In Ghana, whilst we found 19.4% nationally of rural and urban households reported DD purchases in 2016–2017, a study in Tamale found 99.7% of carers of children aged 1–24 months used DD (Inusah et al. 2023). Studies report high DD use in other African cities, including 90.9% in Nansana, Uganda (Ssembuusi et al. 2024) and 85.3% in Gweru, Zimbabwe (Nyamayedenga & Tsvere 2020). Thus, our estimates are consistent with locally high DD use reported in some African cities. Where DD disposal is inadequate, this not only exposes waste collectors to faecal contamination but also households by attracting flies, as animals dig up buried DD, and as pathogens are transmitted by rain, groundwater, or inadvertently during child play (White et al. 2023).

This city-scale DD use survey also has implications for national-level consumption and waste flow analyses using household surveys. Most nationally representative household surveys either do not record the method of solid waste disposal or only capture the main disposal method for mixed waste. Recent country-level analyses of mismanaged plastic waste from vegetable oils (Wright et al. 2022), packaged water (Wardrop et al. 2017), and diapers (Thomas-Possee et al. 2024) based on such surveys therefore assume packaging from these products is disposed of via the main method for mixed waste. Our study shows that this assumption is valid for almost all households in Greater Accra, but approximately one-third of Kisumu households dispose of diapers separately from other waste. Thus, an additional household survey question(s) concerning waste separation and/or secondary waste disposal methods could be introduced in countries with widespread waste separation. This would facilitate a more robust quantification of mismanaged waste from products such as DD. Our study found greater variance in weekly reported DDs purchased, often captured via national household expenditure surveys, e.g. (Ghana Statistical Services 2018), compared to the reported number of DDs used daily. Thus, estimates of DD use from household expenditure surveys will show higher household-level variation in diaper use because bulk purchases affect reported expenditure estimates. Furthermore, in Greater Accra, nearly all mothers wrapped used DD in plastics before disposal, with 42.9% doing so in Kisumu. Thus, this packaging behaviour prior to disposal means that DD consumption generates more plastic waste than would be apparent from DD material composition analyses alone. Kenya's ban on plastic carrier bags (Behuria 2021) may explain the less frequent wrapping of diapers in plastics in Kisumu.

The current local-scale study also confirms DD consumption-smoothing among poorer households, as observed in national expenditure studies (Thomas-Possee et al. 2024). This phenomenon, sometimes referred to as the kadogo (small) economy in East Africa (Mukeku 2018), entails poorer households purchasing goods in small quantities to manage cash flow. Retailers sell DD individually rather than in bulk, thus making them more affordable for poorer households. However, households in Kisumu and Greater Accra reported consuming more DD than estimates from national household expenditure surveys. Kisumu households in the medium wealth quintile used 629 DD/year, whereas analysis of the Kenya Integrated Household Budget Survey suggested 451 DD/year (Thomas-Possee et al. 2024). Similarly, Greater Accra households in this quintile used 1090 DD/year, compared to 301 DD/year estimated from the Ghana Living Standards Survey VII. This suggests that associated national-level mismanaged DD figures may also be underestimated. As the national estimates are derived from lengthy questionnaires covering numerous expenditure items, respondent fatigue in these national household expenditure surveys could account for this discrepancy. Toilet-training age among both Greater Accra and Kisumu respondents is also somewhat later than the 30 and 24 months for Ghana and Kenya nationally (Thomas-Possee et al. 2024), inferred from DD purchases in national household expenditure surveys. This suggests analyses of household expenditure surveys may somewhat underestimate the age of toilet training completion.

Our findings are subject to some limitations, including the potential impact of social desirability bias (Larson 2018). Given that interviews took place in facilities where they could be overheard, respondents may have changed answers to create a positive impression on listeners or for self-deception (to feel good about themselves). The facility setting for interviews prevented survey teams from directly observing housing characteristics, water and sanitation services, or behaviours such as waste disposal and handwashing. This meant we were unable to observe sanitation facility cleanliness or the accessibility and safety of sanitation facilities for young children, which can reduce the risk of unsafe child faeces disposal (Beardsley et al. 2024). Since self-reports typically underestimate the prevalence of undesirable behaviours such as inadequate handwashing (Pavani 2010), these are likely to be under-reported in our survey. Our survey did not capture washing or wiping following child defaecation and thus does not capture additional child faecal management waste such as wet wipes, reported as used in Cambodia (Miller-Petrie et al. 2016). We also did not record whether children were ambulatory, which is associated with increased odds of safe child faeces disposal (Freeman et al. 2016; Majorin et al. 2019). Our study also excluded children aged over 36 months, who are also likely to have used DD, particularly in Kisumu. In classifying waste collection services as an adequate disposal mode, we assume collected waste is safely managed at its final destination.

The sample of children in this study systematically differs from the general population of Kisumu and Greater Accra in several respects, limiting generalisability of our findings. First, participants generally had higher levels of education, sanitation, water, and solid waste collection services than the general population (Table 2). This is likely because our sampling strategy selected contrasting health facilities serving low- or middle-income versus high-income catchment populations, thereby over-sampling those with high incomes in the general population. Second, in our sample, older children were more likely to attend health facilities because of sickness than younger children. Poisson regression (Table 4) did not indicate that attending for sickness affected the reported number of diapers used. However, the participant profile of older children could have systematically differed from the general population because of underlying differences in risk factors for ill health or household characteristics linked to treatment-seeking behaviour. Finally, our sample excluded carers of children less than 18-years-old.

As a commodified form of sanitation, DDs constitute an example of the growing commodification of Water, Sanitation, and Hygiene (WASH). Our study finds that DD consumption is near-universal in the populations of Kisumu and Greater Accra, although poorer households ration their DD use. Approximately a third of this consumption occurs in households lacking adequate solid waste disposal services in Kisumu, leading to leakage of used DD into the environment. However, across all wealth quintiles, children's carers consistently report convenience and hygiene benefits for their children from using DD. Literature on US diaper banks providing free DD finds benefits to children's carers from DD use, particularly greater opportunity for employment, improved well-being, and greater childcare. Thus, in formulating a policy response to extensive diaper use, there is a need to balance the environmental and public health risks of inadequate DD disposal with the benefits to mothers and children's carers of DD. A complete ban on DD would risk undermining their potential benefits, while continued unregulated growth of DD consumption in the absence of greater solid waste collection service coverage risks significant environmental damage. Waste management systems that enable the safe separation of used DD from other solid waste and their subsequent disposal would address the latter concern. Such technologies include the biodegradation of DD, sometimes coupled with fungi cultivation or compost production, incineration with energy recovery, and pyrolysis (thermal degradation in an oxygen-free environment) (Khoo et al. 2019). The JMP currently considers DD disposal as solid waste appropriate if waste is stored, collected, and disposed of in a sanitary manner (WHO/UNICEF 2018). In the long term, safe separation of DD waste with subsequent treatment via these technologies could be considered appropriate disposal for monitoring purposes.

In future research, there is thus a need to quantify the potential benefits of DD for mothers and children's carers to inform policy. There is also a need to develop and expand waste management systems for safely separating used DD from other solid waste, including their social acceptability, technical viability, impact on household exposure to faecal contamination, related diarrhoea risk, and barriers to system scale-up.

The work was undertaken through the ‘Expanding safe water and waste management service access to off-grid populations in Africa’ project, funded through the UKRI Collective award via the Global Challenges Research Fund (ref: ES/T008121/1). The support of the UK Economic and Social Research Council (ESRC) is gratefully acknowledged.

Author contributions were as follows: conceptualised by HAG, TMLH, DM, WJA, OJ, AM; investigated by AM, OJ, OL, BE, AJ; wrote the original draft: AM, WJA; wrote and review and edited by HAG, TMLH, DM, OJ, BE, AJ, OL; provided rendered support in formal analysis and visualised by AM, WJA; project administrated by WJA, DM, OJ, OL, AJ; provided rendered support in funding acquisition by WJA, DM, OJ, OL.

The study was approved by the Faculty of Environmental and Life Sciences Ethical Review Committee, University of Southampton, UK (Ref: 77654, approval date: 27 October 2022), by the Ethics Review Office of Jaramogi Oginga Odinga University of Science and Technology, Kenya (Ref no. ERC 34/11/22-07/03; approval date: 1st Nov 2022), and by the Institutional Review Board of the Noguchi Memorial Institute for Medical Research, University of Ghana (Ref: 003/20-21 amend 2022; approval date: 9th December 2022). The study also received ethical approval from Ghana Health Services (Ref. no. GHS-ERC:022/05/23; approval date: 15th June 2023) and from the Aga Khan ethical review board (Ref: ADM/007/911, 3rd October 2023), an ethical review board overseeing facility-based research within a major Kenyan private healthcare provider network. To seek consent from study participants, the participant information was first read and explained in the local dialect to them through a translator, and written consent was sought thereafter.

All relevant data are available from https://dx.doi.org/10.5255/UKDA-SN-856911.

The authors declare there is no conflict.