A 30-year trend of dairy consumption and its determinants among income groups in Iranian households

Introduction

Milk and dairy products provide essential nutrients and have the potential to prevent chronic diseases, thus reducing healthcare costs. However, there is a lack of consistent and updated data on dairy consumption trends in Iran. This study aims to analyze the trends in dairy consumption among Iranian households from 1991 to 2021, focusing on household-level determinants across different expense groups.

Methods

The study uses data from the Iranian Household Expenditure and Income Survey conducted annually from 1991 to 2021 to analyze households' dairy consumption. The data includes values and expenses of food and non-food items purchased in the previous month, as well as demographic characteristics of household members. The households were categorized into 10 deciles based on their gross expense. The econometric model used weighted mean per capita milk, yogurt, cheese, and total dairy consumption based on milk equivalent for each decile. The model takes into account changes in income, prices, household composition, education level, occupation, and residency area using panel data. Data preparation and model estimation were performed using RStudio and STATA17 software.

Results

Based on the findings, in 1991, per capita milk, yogurt, and cheese consumption were 26.77 kg, 16.63 kg, and 2.42 kg, respectively. By 2021, these figures changed to 22.68 kg, 11.06 kg, and 3.79 kg, reflecting a decrease in milk and yogurt consumption but an increase in cheese consumption. Family size was positively correlated with yogurt consumption and head of the household spouse's job score were positively correlated with milk, yogurt and cheese consumption. Also, the presence of under five-year-old children and older adults members (over the age of 60) in the household was inversely related with yogurt and cheese consumption. Female-headed households tended to purchase more cheese, while their milk purchase level was significantly lower. Residing in urban areas was negatively related to milk, while cheese and total dairy consumption was higher in urban areas.

Discussion

The findings highlight the importance of targeted dairy subsidy interventions and educational programs to improve dairy consumption in Iranian households, especially among vulnerable groups. This will require urging policymakers and food system stakeholders for effective strategies that address macro-level factors to promote dairy consumption.

Evaluating Population Density as a Parameter for Optimizing COVID-19 Testing: Statistical Analysis

Background

SARS-CoV-2 transmission risk generally increases with the proximity of those shedding the virus to those susceptible to infection. Thus, this risk is a function of both the number of people and the area they occupy. However, the latter continues to evade the COVID-19 testing policy.

Objective

The aim of this study is to analyze per capita COVID-19 testing data reported for Alabama to evaluate whether testing realignment along population density, rather than density agnostic per capita, would be more effective.

Methods

Descriptive statistical analyses were performed for population, density, COVID-19 tests administered, and positive cases for all 67 Alabama counties.

Results

Tests reported per capita appeared to suggest widespread statewide testing. However, there was little correlation (r=0.28, P=.02) between tests per capita and the number of cases. In terms of population density, new cases were higher in areas with a higher population density, despite relatively lower test rates as a function of density.

Conclusions

Increased testing in areas with lower population density has the potential to induce a false sense of security even as cases continue to rise sharply overall.

Fish Consumption for the Adult Population of Hawai'i, Collected with a Self-Reported Household Survey

The population of Hawai'i has traditionally been high in average fish consumption when compared to the national average. However, information is lacking on patterns of fish consumption among subpopulations. Data on fish consumption in the last 30 days from 11,293 adults was collected with the use of the Hawai'i Health Survey (an annual telephone survey of households and household members) during the years 2007 and 2008 and weighted to represent the adult population of Hawai'i. The US Department of Agriculture's, Environmental Protection Agency, and the United States Food and Drug Administration, recommend 8-12 ounces of fish per week for associated health benefits. Present estimates of fish consumption were skewed to the right (mean 10.5 and median 7.9 ounces) with some adults eating large amounts of fish per day and frequently. It may be of concern, given high amounts of methylmercury in select fish, that 13.7% of adults were eating fish 20 or more times per month. In addition, the serving size increased with increasing number of times per week fish was eaten. The subpopulation variables examined included age, sex, marital status, education, ethnicity, poverty, and demographics representing the adults of Hawai'i. The prevalence of adults consuming 8 or more ounces was highest for other than Honolulu counties, men, ages 18-74, married, with at least one year of college, Filipino and Native Hawaiian ethnicities (White, Japanese, Chinese, and All Others were also examined), employed, and adults living with higher income levels (lower poverty). However, only an estimated 46.9% of adults in Hawai'i were eating the eight or more ounces of fish weekly. Prevalence was lowest for women, Chinese, age >74 years, and the City and County of Honolulu. Adults who rated their general health better (excellent/good compared to fair/poor) were more likely to consume 8 or more ounces of fish per week, significantly for men. Men who rated their physical health higher and their mental health higher (via Optum SF™ Health Surveys) were associated with higher prevalence of consuming 8 or more ounces of fish per week. Higher consumption of the beneficial omega-3 fatty acids associated with fish low in methylmercury needs to be encouraged for those not meeting the recommended ounces of fish per week, particularly women, Chinese, older age groups, and adults living below the poverty level.

Processes and impacts of acid discharges on a natural substratum under a landfill

Analyses of substratum samples under a landfill were performed to assess the pollution impact of waste over a clay-sand material after nine years of exposure. These samples presented different illite/kaolinite ratios and an acid pH, especially low near the waste/soil contact in a 1-1.5 m soil thickness with low density and despite the basic pH of the collected actual methanogenic leachate. This study has raised the effects of a presumably acid stage in the waste leachate on the substratum final quality of clay and its physical-chemical properties as an attenuation buffer. These effects were the dissolution of carbonate minerals, decrease of dry density, increase of hydraulic conductivity, release of metals and formation of clays with low cationic exchange capacity (CEC) as kaolinite. The large presence of H(+) and Al(OH)(3-x)(x+) depleted the neutralizing capacity of the substratum and occupied exchangeable sites, decreasing therefore the available sites for retaining leachate pollutants, which traveled further than the first-meter depth of the substratum. In order to combat and prevent pollution as well as to preserve the good barrier properties under new landfills it is proposed to select illitic materials better than kaolinitic substratum, to avoid acid landfilling and if not possible to add lime.