Background and objectives: Lifestyle-related risks are linked to several non-communicable diseases, with enormous global mortality and economic cost. Women in Saudi Arabia are faced with high prevalence of obesity, inactivity and sedentary behaviours. This study examined the interaction effects of gender with obesity status and lifestyle behaviours among Saudi adolescents.

Methods and study design: A total of 2888 adolescents (1500 females) aged 15-19 years were randomly selected from secondary schools in three major cities in Saudi Arabia, using a multistage stratified cluster sampling technique. Weight, height and waist circumference were measured and physical activity (PA), screen time, sleep duration and dietary habits were assessed using a validated questionnaire. ANCOVA and multivariate tests were used while controlling for age.

Results: A number of lifestyle behaviours displayed significant gender effects, with some selected variables having multiple interaction effects. Total activity energy expenditure and sum of vigorous-intensity PA showed significant interaction effects between gender and obesity status, whereas sum of moderate activity energy expenditure, non-leisure-time PA and sleep duration exhibited significant interaction effects between gender and screen time. Vegetable intake showed significant three-way interaction effects between gender, waist/height ratio and screen time.

Conclusions: The presence of several lifestyle behavioural risks, including physical inactivity, sedentary behaviours and some dietary habits was confirmed. The high inactivity level and screen time represents a double burden on the health of young Saudi females. Future studies must address the psycho-social, cultural and environmental determinants associated with healthy lifestyle relative to gender and initiate novel interventions to reduce sedentary behaviour. and future nutrition science degrees and lead to improved employability skills of nutrition science graduates.