risk factors

TABLE 4.2 Overview of assumptions for models 1–10 and corresponding risk factors

MODELS RISK FACTORS CHANGE TO RISK FACTORSa DESCRIPTION

1 Overweight. obesity

2 Overweight, obesity 3 Overweight obesity 4 Insufficient fruit and vegetable intake 5 Insufficient fruit and vegetable intake 6 Insufficient physical activity

7 Insufficient physical activity

8b Overweight, obesity 0%

–10%

–20%

0%

–10%

0%

–10%

–1.4 to + 4.8% + 15.4 to 22.6% Baseline scenario of no change to risk factors; reference group for models 2 and 3 Moderate intervention of 10% reduction to risk factors

Ambitious scenario of 20% reduction to risk factors

Baseline scenario of no change to risk factors; reference group for model 5 Moderate intervention of 10% reduction to risk factors

Baseline scenario of no change to risk factors; reference group for model 7 Moderate intervention of 10% reduction to risk factors

Baseline scenario of increasing prevalence of risk factors; reference group for models 9 and 10.

9 Overweight, obesity –10% Moderate intervention of 10% reduction to risk factors

10 Overweight, obesity –20% Ambitious scenario of 20% reduction to risk factors

Source: World Bank data. a. corresponds to percent change per decade. b. For model 8, we used sex-specific projections of overweight and obesity from 2013 to 2030 from Lo et al. (2014). We calculated a year over year rate to arrive at the 10-year change. See corresponding prevalence table 4.3 for increasing scenario for more details. Prevalence of obesity was projected to increase for both males and females. However, for overweight prevalence, there was a small decrease for males and an increase for females.

of NCD premature mortality and disability. Model 1 assumes no changes in risk factors, in that no interventions have occurred (that is, there has been no government intervention and no increase in prevalence). This model applies agespecific risks of disease for the key NCD conditions as a function of exposure to key risk factors—overweight and obesity. These age-specific risk estimates were used to arrive at DALYs, HALEs, ex0 (calculation 4.2), and deaths by sex. All of the forecasts assume decreasing fertility trends, aging of the population, and decreases from mortality and morbidity from disease for all age groups, based on UN Population Estimates (UN DESA 2019b). Models 2 and 3 in this chapter are calculated as deviations from model 1, the baseline scenario.

Next, the NCD disability was forecasted to 2050 using different assumptions about modification in risk factors. Model 2 (moderate intervention) assumes that Saudi Arabia will adopt some governmental policy changes and that these changes will be mildly successful. Moderate success is considered to be a 10.0 percent reduction in the prevalence of overweight (BMI = 25.0–29.9 kg/m2) and obesity (BMI > 30) every 10 years. For example, the current overweight prevalence for women in Saudi Arabia in 2020 is estimated at 32.7 percent (MOH 2020). If a 10.0 percent reduction in obesity prevalence every 10 years is assumed, then a moderate intervention scenario forecasts the following obesity prevalence among women:

• 2030: 32.7% × 0.90 = 29.4% • 2040: 32.7% × (0.90 x 0.90) = 26.5% • 2050: 32.7% × (0.90 x 0.90 x 0.90) = 23.8%

Model 3, which is the ambitious scenario, assumes that policy interventions will aggressively target reducing both overweight and obesity prevalence. The ambitious scenario of model 3 assumes a 20 percent reduction in overweight and obese population every 10 years.

Unhealthy diet (low fruit and vegetable intake)

The NCD burden associated with low fruit and vegetable intake was quantified using the life tables to obtain 2030, 2040, and 2050 forecasts of NCD premature mortality and disability. Model 4 assumes no changes to the population’s fruit and vegetable intake. Age-specific risks were calculated for stroke, ischemic heart disease, and colon cancer as a function of exposure to insufficient fruit and vegetable intake. These age-specific risk estimates were used to arrive at DALYs and deaths averted by sex (UN DESA 2019a; WHO 2004).

NCD disability was forecasted into 2030, 2040, and 2050 assuming a 10 percent reduction in insufficient fruit and vegetable intake each decade. Model 5 (moderate intervention) assumes that Saudi Arabia will adopt some governmental policy changes and that these changes will focus on increasing fruit and vegetable intake in the population. Moderate success is considered to be a 10 percent increase in the prevalence of sufficient fruit and vegetable intake (five servings per day). Model 4 serves as the baseline scenario for model 5.

Insufficient physical activity

Estimates of the NCD burden associated with the prevalence of insufficient physical activity was applied to the life tables to arrive at 2030, 2040, and 2050 forecasts of NCD premature mortality and disability. Model 6 is a no-change scenario that assumes that the prevalence of insufficient physical activity will remain unchanged from 2020. This model assumes that no interventions have occurred (that is, there has been no government intervention and no increase in the prevalence of risk factors). Age-specific risks of disease for stroke, ischemic heart disease, diabetes, breast cancer, and colon cancer were calculated as a function of exposure to insufficient physical activity (IMHE 2018a). These age-specific risk estimates were used to arrive at DALYs and deaths averted, by sex (UN DESA 2019a; WHO 2004).

NCD disability and premature mortality were forecasted for 2030–50 assuming a 10 percent increase in sufficient physical activity for each decade. Model 7 (moderate intervention) assumes that Saudi Arabia will adopt some governmental policy changes and that these changes will be mildly successful. Moderate success is considered to be a 10 percent increase in the prevalence of sufficient physical activity (150 minutes of exercise per week).

Overweight and obesity, increasing prevalence

Models 8, 9, and 10 assume that overweight/obesity prevalence will increase by 1.2 percent and 19.6 percent, respectively (Lo et al. 2014). Model 8 assumes no changes in risk factors and that no interventions have occurred (that is, no government intervention and no increase in prevalence). Models 9 and 10 in this chapter are calculated as deviations from model 8, the increasing scenario.

The NCD burden due to premature death and disability was forecasted to 2050 using different assumptions about modification in risk factors. Model 9 (moderate intervention) assumes a moderate reduction of 10 percent to overweight (BMI = 25.0–29.9 kg/m2) and obesity (BMI ≥ 30) prevalence every 10 years. The ambitious scenario, model 10, assumes a 20 percent reduction in overweight/obesity every 10 years.