Research Spotlights: November 2023

Modulating effect of the gut microbiome on the effect of second-hand smoke exposure on behavioral and cognitive performance: a mouse model

Second-hand smoke (SHS) exposure is a significant global health risk which has been associated with neurological impairments and neurodegenerative diseases. However, the biological mechanisms underlying how SHS affects the brain remain unclear. Previous research has highlighted a link between the gut microbiome and cognitive and behavioral performance via the gut-brain axis. In a recent publication, researchers supported by NIEHS, NIA, and others investigated whether SHS exposure induces gut microbial alterations.

The researchers used two strains of mice and exposed them to air with and without 30 mg per cubic meter of SHS over 10 months. They assessed microbiota diversity in fecal samples. They also administered behavioral tests to assess SHS effects on memory and learning. Their analytic models included SHS exposure, genotype, sex, and several behavioral physiological covariates.

The results demonstrate that SHS exposure influences gut microbial composition, biodiversity, and evenness in a sex-dependent manner. The alterations in gut microbiome biodiversity and composition were associated with various measures of cognitive function, supporting the hypothesis that intestinal microbiota may be part of the causal pathway between SHS exposure and cognitive abilities. Additionally, SHS exposed animals showed elevated levels of biomarkers for brain oxidative stress, indicating that SHS exposure may accelerate brain aging. This effect varied by the strain of mouse and interacted with sex. Additional studies could further elucidate the causal role of the microbiome in the effects of SHS on the brain and cognition.

Raber J, Stagaman K, Kasschau KD, Davenport C, Lopes L, Nguyen D, Torres ER, Sharpton TJ, Kisby G. Behavioral and Cognitive Performance Following Exposure to Second-Hand Smoke (SHS) from Tobacco Products Associated with Oxidative-Stress-Induced DNA Damage and Repair and Disruption of the Gut Microbiome. Genes (Basel). 2023 Aug 27;14(9):1702. doi: 10.3390/genes14091702. PMID: 37761842; PMCID: PMC10531154.

Disparities in sleep-wake patterns by labor force status: Population-based findings

Sufficient sleep is crucial for maintaining heath, and sleep insufficiencies are associated with mental and physical health conditions, including major depressive disorder, obesity, diabetes, and cardiovascular diseases. Previous studies have found associations between sleep duration and socioeconomic status (SES), employment status, the presence of children in the household, age, gender, and ethnicity/race. Individuals who are unemployed often report less than ideal sleep duration and poor sleep quality. In a recent publication supported by NHLBI and NINDS, researchers investigated differences in sleep-wake patterns by labor force status (employed, unemployed, and out of the labor force) along with sociodemographic variables.

The researchers used data from the American Time Use Survey (ATUS) which included a nationally representative sample of adults (N=130,062, aged 25–60 years), with an average age of 42 years, 51% identifying as female, 68% Non-Hispanic White, 79% employed, and 90% having attained high school education or higher. ATUS respondents were classified into three categories: “employed”, “unemployed”, and “not-in-the-labor-force”. Individual sleep-wake patterns were extracted from time use logs. Neighborhood covariates included seasonally adjusted employment status, marital status, age, gender, race/ethnicity, and educational attainment. The researchers predicted changes in intra-person sleep-wake patterns through hypothetical employment status changes, e.g., employed to unemployed or not-in-the-labor-force, with gender, race/ethnicity, and educational attainment as potential moderators.

The results indicated that labor force status was associated with sleep-wake patterns overall. There were interactions in predicted changes in sleep-wake patterns by labor force status and race/ethnicity, such that a shift from “employed” to “unemployed” resulted in delayed wake time that was most pronounced for Hispanic and Non-Hispanic White individuals, and less so for non-Hispanic Black respondents. Non-Hispanic Whites and Asians displayed the highest probability to engage in mid-day napping if transitioning from “employed” to “not-in-the-labor-force” states. Having a high school education or an advanced degree was predicted to have a higher tendency for midday napping when labor force status changed from “employed” to “unemployed”. In summary, this study further supports the importance of understanding relationships between labor force status, sleep-wake cycles, and sleep health disparities.

Lyu X, Dunietz GL, O'Brien LM, Chervin RD, Koumpias A, Shedden K. Disparities in sleep-wake patterns by labor force status: Population-based findings. Chronobiol Int. 2023 Aug;40(8):1111-1122. doi: 10.1080/07420528.2023.2253904. Epub 2023 Sep 10. PMID: 37691398.

Results from "Live Well", a randomized controlled community-based participatory intervention to prevent obesity in new immigrant mother-child dyads

Immigrants who move to the U.S. often experience weight gain, which results in disproportionate rates of overweight and obesity among populations that formerly had a lower prevalence of overweight and obesity than their U.S.-born counterparts. Researchers, supported by NICHD and others, assessed whether an intervention developed with active input from community partners could prevent unhealthy weight gain among new immigrant (≤ 10 years in the U.S.) mothers and children in the Greater Boston area.

“Live Well” was a community-based participatory research (CBPR) randomized controlled intervention that ran from 2008 to 2012. The research team provided culturally relevant, evidence-based, and community-centered interventions in support of healthy nutrition and physical activity patterns to new immigrants early in their acculturation process. Participants were mother-child dyads from Brazil, countries within Latin America, and Haiti, who were recruited into two cohorts and randomized to either a control group (n = 177, mean age of 36.6 years) or intervention group (n = 188, mean age of 35.9 years). Mothers in both groups had resided in the U.S. for an average of six years; 65.7% of the control group and 75% of the intervention group had completed high school. Approximately three-quarters of mothers in both groups were classified as overweight or obese, while slightly under half of the children in both groups were classified as overweight or obese.

The researchers collected height and weight to calculate BMI scores for mothers and BMI z-scores for children. Surveys at baseline and follow-up measurement days were used to collect sociodemographic variables, parent acculturation, and behavioral measures. Trend differences in outcomes from baseline were assessed at six-month intervals until the year 2 mark from the start of the intervention. Results were inconsistent at lower levels of participation, but mothers who engaged in all 12 sessions during the first year had significantly larger reductions in BMI scores at 18 months and 24 months.

In summary, this study demonstrates the potential viability of using a CBPR approach to address unhealthy weight gain and obesity among immigrant mothers. The authors note that since there were lower-than-anticipated maternal participation rates in the intervention, additional research is warranted to optimize this intervention.

Economos CD, Tovar A, Choumenkovitch S, Boulos R, Chui K, Gute DM, Hyatt RR, Metayer N, Pirie A, Must A. Results from "Live Well", a randomized controlled community-based participatory intervention to prevent obesity in new immigrant mother-child dyads. BMC Public Health. 2023 Oct 2;23(1):1893. doi: 10.1186/s12889-023-16727-z. PMID: 37784070; PMCID: PMC10544478.