Estimating the potential impact fraction of hypertension as the main risk factor of stroke: Application of the distribution shift method

Modelling the impacts of volumetric and minimum unit pricing for alcohol on social harms in Australia

AIMS

Alcohol pricing policies may reduce alcohol-related harms, yet little work has been done to model their effectiveness beyond health outcomes especially in Australia. We aim to estimate the impacts of four taxation and minimum unit pricing (MUP) interventions on selected social harms across sex and age subgroups in Australia.

METHODS

We used econometrics and epidemiologic simulations using demand elasticity and risk measures. We modelled four policies including (A) uniform excise rates (UER) (based on alcohol units) (B) MUP $1.30 on all alcoholic beverages (C) UER + 10 % (D) MUP$ 1.50. People who consumed alcohol were classified as (a) moderate (≤ 14 Australian standard drinks (SDs) per week) (b) Hazardous (15-42 SDs per week for men and 14-35 ASDs for women) and (c) Harmful (> 42 SDs per week for men and > 35 ASDs for women). Outcomes were sickness absence, sickness presenteeism, unemployment, antisocial behaviours, and police-reported crimes. We used relative risk functions from meta-analysis, cohort study, cross-sectional survey, or attributable fractions from routine criminal records. We applied the potential impact fraction to estimate the reduction in social harms by age group and sex after implementation of pricing policies.

RESULTS

All four modelled pricing policies resulted in a decrease in the overall mean baseline of current alcohol consumption, primarily due to fewer people drinking harmful amounts. These policies also reduced the total number of crimes and workplace harms compared to the current taxation system. These reductions were consistent across all age and sex subgroups. Specifically, sickness absence decreased by 0.2-0.4 %, alcohol-related sickness presenteeism by 7-9 %, unemployment by 0.5-0.7 %, alcohol-related antisocial behaviours by 7.3-11.1 %, and crimes by 4-6 %. Of all the policies, the implementation of a $1.50 MUP resulted in the largest reductions across most outcome measures.

CONCLUSION

Our results highlight that alcohol pricing policies can address the burden of social harms in Australia. However, pricing policies should just form part of a comprehensive alcohol policy approach along with other proven policy measures such as bans on aggressive marketing of alcoholic products and enforcing the restrictions on the availability of alcohol through outlet density regulation or reduced hours of sale to have a more impact on social harms.

Effect of Intensive Blood Pressure Control on Incident Stroke Risk in Patients With Mild Cognitive Impairment

BACKGROUND

Patients with mild cognitive impairment may be at higher risk of incident stroke, but the effect of intensive blood pressure (BP) control on that risk has not been explored.

METHODS

We performed a post hoc analysis of SPRINT (Systolic Blood Pressure Intervention Trial) and included patients with a baseline Montreal Cognitive Assessment score of 19 to 25 and without a prior history of stroke. The primary outcome was incident stroke (ischemic and hemorrhagic) during follow-up. We report the unadjusted cumulative risk of our primary outcome by SPRINT randomization arm (intensive versus standard BP control) and also fit Cox models to the primary outcome and adjusted for patient age at randomization, race/ethnicity, sex, baseline BP, atrial fibrillation, diabetes, and smoking.

RESULTS

We included 5091 patients (mean age 68.2, 44% female, 56.7% non-Hispanic White, and 50.2% randomized to intensive BP control), of which 95/5091 (1.9%) had an incident stroke during a mean of 3.8±0.9 years of follow-up. The risk of incident stroke in patients randomized to standard BP control was 57/2536 (2.3%) and to intensive BP control was 38/2555 (1.5%; P=0.045). In the adjusted Cox model, the hazard ratio for incident stroke events with intensive BP control was 0.65 (95% CI, 0.43-0.98; P=0.040).

CONCLUSIONS

Although the SPRINT trial failed to show a reduction in stroke with intensive BP control for all subjects, those with a Montreal Cognitive Assessment score consistent with mild cognitive impairment at baseline had an association between intensive BP control and lower risk of incident stroke. Future trials of primary prevention of stroke may benefit from enrichment using baseline vascular biomarkers of elevated risk, such as mild cognitive impairment.

How much excess weight loss can reduce the risk of hypertension?

Background

A 25% relative reduction in the prevalence of hypertension is a global target. This meta-analysis estimated the effect of excess weight loss on hypertension.

Methods

We searched PubMed, Web of Science and Scopus until January 2016. We included prospective cohort studies addressing the association between overweight/obesity and hypertension. We expressed the strength of association using risk ratio and the excess risk using attributable risk fraction with 95% CI based on the random-effects model.

Results

We found 7617 references and included 10 studies with 173 828 participants. Compared with normal weight, the risk ratio of hypertension was 1.52 (1.37, 1.67; 9 studies, I2 = 82.4%) for overweight and 2.17 (1.84, 2.50; 9 studies, I2 = 88.9%) for obesity. The excess risk of hypertension attributable to overweight was 32% (24%, 40%; 8 studies, I2 = 85.5%) and that attributable to obesity was 47% (40%, 54%; 8 studies, I2 = 88.2%). That means, excess weight loss may reduce the risk of hypertension by between 24% and 40% in people who are overweight and by between 40% and 54% in people who are obese.

Conclusions

Excess weight loss is a vital strategy for controlling hypertension and is sufficient for achieving the global target, particularly if it is accompanied with other preventive measures.

Population-attributable fraction of hypertension associated with obesity, abdominal obesity, and the joint effect of both in the Central Provinces of Iran

The prevalence of obesity has been increasing in Iran over the past decade. This study aimed to determine the population-attributable fraction (PAF) of hypertension associated with obesity, abdominal obesity, and the joint effect of both in the central provinces of Iran. Prevalence of hypertension was extracted from the Iranian Ministry of Health Non-Communicable Disease Risk Factor InfoBase 2009. Measure of association between obesity and hypertension was extracted from Tehran Lipid and Glucose Study, for males and females, in order to calculate the PAF of hypertension associated with obesity. Age standardization of the reported prevalence of obesity was done using the World Health Organization method. The PAF of hypertension associated with the joint effect of obesity and abdominal obesity in females was highest in Semnan Province: 22.7 [95% confidence interval (CI): 4.2–35.6], followed by Qom 21.09 (95% CI: 3.7–33.1), and Yazd 20.3 (95% CI: 3.5–32.1). In males, the highest PAF was observed in Qom Province 31.07 (95% CI: 16.7–41.1), followed by Semnan 29.6 (95% CI: 15.9–39.3), Qazvin 25.9 (95% CI: 13.7–34.5), Tehran 24.2 (95% CI: 12.7–32.3), and Isfahan 20.4 (95% CI: 3.5–27.4). Prevalence of hypertension is higher in more developed provinces. PAFs suggest that a sizable share of hypertension in these provinces is associated with obesity. It is recommended that health promotion programs focus on obesity in the provinces with a higher share of hypertension due to obesity.

The flavor and acceptability of six different potassium-enriched (sodium reduced) iodized salts: a single-blind, randomized, crossover design

Background

Hypertension is a serious public health problem. Potassium-enriched salt is suggested as a tool for lowering blood pressure. However, its flavor and taste acceptability is essential for population-based salt reduction strategy and needs to be well-understood. This trial assessed the flavor and taste acceptability of six different potassium-enriched iodized salts in the general population.

Methods

We conducted this crossover trial from May to June 2016, enrolling 100 normal volunteer subjects aged 11 to 64 years. We compared regular sodium chloride salt (placebo) with six different potassium-enriched (sodium reduced) iodized salt (experiment), including 0 %, 5 %, 10 %, 15 %, 20 %, 25 %, and 30 %. The participants served as their own control and received a placebo and a sequence of the experiments. They tasted the two salts sequentially and stated their preference and acceptance. Each subject received all salts.

Results

More than 80 % of participants who either did not distinguish between the two salts even in high potassium-enriched salts or preferred potassium-enriched salt (P < 0.001). The number of participants who preferred the flavor of potassium-enriched salt was greater than the number of subjects who preferred the flavor of regular sodium chloride.

Conclusion

Our findings indicated that the six different potassium-enriched salts had a public acceptability of at least 80 % among normal subjects from the general population. Although the acceptability of the potassium-enriched salts by a more general population group would require to be confirmed, universal use of this salt may help us achieve the target of 30 % relative reduction in mean population intake of sodium by 2025.

How much excess body weight, blood sugar, or age can double the risk of hypertension?

BACKGROUND

Despite the well-known impact of advanced age, excess body weight, and raised blood glucose on blood pressure, the level of exposure to these risk factors that is necessary to double the risk hypertension is not widely investigated, but was explored in this study.

STUDY DESIGN

Cross-sectional study.

METHODS

This study reports the results of a screening program conducted on a large population of adults to assess the prevalence of diabetes and hypertension and their associated risk factors. The participants were people aged 30 years or older referring to 16 health centers in Tehran. A standard questionnaire was used to collect data on blood pressure, body mass index (BMI), waist-hip ratio (WHR), fasting blood sugar (FBS), smoking status, and demographic characteristics (age and gender) based on WHO STEPS manual.

RESULTS

Of the 7611 people who participated in the screening program, 696 (9.1%) had raised blood pressure. The level of exposure to risk factors for high blood pressure that is necessary to replicate the OR of 2.0 indicated that an OR of 2.0 corresponds to an increase in age of about 9.4 years, an increase in BMI of about 10.3 kg/m(2), an increase in waist-to-hip ratio of about 0.5, and an increase in fasting blood sugar (FBS) of about 85.8 mg/dl.

CONCLUSIONS

This study indicated how much increase in age, BMI, waist-hip ratio, and FBS can double the risk of hypertension. These results may be helpful for public health policy and prioritizing effective prevention programs to reduce the burden of high blood pressure.