Rural preschoolers face higher risk of overweight and abdominal obesity

New research being presented at this year's European Congress on Obesity (ECO) in Malaga, Spain (11-14 May), reveals that 3- to 4- year olds in rural areas are more likely to be living with overweight and abdominal obesity (excess fat around waist), and spend more time on screens than their urban counterparts. 

Our findings reveal distinct patterns of how physical activity, screen time, and sleep relate to overweight and abdominal obesity in urban and rural settings, indicating that one-size-fits-all strategies to tackle overweight and obesity in early childhood are unlikely to be effective."

Karoliina Uusitalo, lead author, doctoral researcher from the Folkhälsan Research Center and the University of Helsinki, Finland

Around 1 in 3 children in the WHO European Region is living with overweight or obesity [1], with an estimated 17 million boys and 11 million girls (aged 5-19 years) predicted to be living with obesity in Europe by 2035 [2]. Identifying those children most at risk and the environmental and geographic factors that contribute to this risk is critical to focusing prevention efforts.

Movement behaviours-insufficient physical activity, excessive sedentary behaviour (such as screen time) and poor sleep-are potential risk factors for overweight and obesity in children, but evidence in young children is inconsistent and primarily focused on body mass index (BMI), which may misrepresent true adiposity, as it fails to account for differences in body composition, such as fat distribution and muscle mass. Additionally, the effects of urbanisation on movement behaviours and adiposity in young children remain poorly understood.

To explore these issues further, researchers examined the urban-rural differences in movement behaviours (physical activity, sedentary time, screen time, and sleep) and adiposity indicators (BMI and waist-to-height ratio [WHtR]) in 1,080 3–4 year-old participants (46% girls) from the SUNRISE Finland study [3]-part of the international SUNRISE study, which aims to monitor the WHO Guidelines on physical activity, sedentary behaviour and sleep for children under 5 years globally [4]. Researchers also examined the associations between movement behaviours and adiposity indicators separately for urban and rural areas.

In 2022−2023, participants living in both urban (57%) and rural (43%) areas of Finland wore an ActiGraph accelerometer on their waist for one week to assess different intensities of physical activity and sedentary time, and parents reported children's sleep and screen time, as well as their consumption frequency of sugary drinks and unhealthy snacks.

Researchers measured children's height, weight and waist circumference to calculate BMI and weight categories (normal weight [including thinness] and overweight [including obesity]) according to sex and age using Finnish reference values, with a WHtR of 0.55 or higher indicating abdominal obesity.

The results were adjusted for potentially confounding factors like age, sex, data collection area, household education, sugary drinks and unhealthy snacks (and additionally for accelerometer wear time for physical activity and sedentary time) .

The analysis revealed clear rural-urban differences in patterns of adiposity, with 24% of 3-4 year olds in rural areas living with overweight or obesity compared to 16% of those in urban areas. Similarly, around 19% of rural preschoolers had abdominal obesity compared to 13% in urban environments.

Preschoolers living in rural areas also slept more (on average 11 h 19 min vs. 11 h 11 min) and had more screen time (1 h 26 min vs. 1 h 14 min) per 24 hours than their urban counterparts.

The researchers also found that higher moderate to vigorous intensity physical activity (e.g., running and energetic play) in urban environments and higher light physical activity (e.g., low-energy play) in rural areas were linked with a higher risk of overweight (based on BMI), but not with abdominal obesity (based on WHtR).

"This finding may reflect that waist-to-height ratio is a better indicator of adiposity, whereas BMI does not distinguish between fat and muscle mass, which tends to increase with higher physical activity," said Uusitalo.

Only in rural areas was more screen time associated with a higher risk of both overweight and abdominal obesity.

According to co-author Dr. Elina Engberg from the Folkhälsan Research Center and the University of Helsinki in Finland, "The stronger association between screen time and adiposity indicators in rural areas may be partly explained by the higher screen time observed among rural children, whereas other factors appear to play a more significant role in adiposity in urban areas."

She continues: "The health consequences and persistence of young childhood obesity into adulthood highlight the need for efforts to improve society and family-oriented preventive strategies at the local level, which could narrow the gap in risk for young children in rural settings."

This is a cross-sectional study, and as such, no firm conclusions can be drawn about cause. And the researchers acknowledge that reverse causality-whereby more screen time might be a consequence of overweight and abdominal obesity rather than the other way round-might explain the associations found. The study also relied on parent assessment rather than objective measures of screen time and sleep patterns. Strengths of the study include a relatively large sample of young children, the use of measured height, weight, and waist circumference, as well as device-based assessment of physical activity and sedentary time.