Sex-specific associations between screen time and lipoprotein subfractions

Effects of electronic screen exposure time on hypertensive disorders in pregnancy: a retrospective cohort study

BACKGROUND

We previously conducted a case-control study and found that exposure to electronic screen before nocturnal sleep was associated with hypertensive disorders in pregnancy (HDP). Hence, we carried out this cohort study aiming to identify the effects of screen exposure time on the incidence rate and severity of HDP.

METHODS

A retrospective cohort study was conducted from January 2022 and July 2022 from three hospitals in Wuxi and Changzhou cities. A total of 732 women were recruited and the information included socio-demographic characteristics, screen exposure and outcomes. Generalized estimating equations and binary non-conditional logistic models were applied to multivariate analysis, calculating the odds ratios (ORs) and 95% confidence intervals (CIs) of screen exposure time.

RESULTS

The duration order of total screen time was smartphone > computer > television, while the duration order of screen time before nocturnal sleep was smartphone > television > computer. Multivariate analyses showed that the susceptibility of HDP among women who exposed to television before nocturnal sleep was 81.5% percent higher than those not exposed (P = 0.018, OR[95%CI] = 1.815[1.106-2.981]). In addition, total daily exposure time of television in the third trimester of pregnancy significantly increased the severity of HDP (P = 0.021, OR[95%CI] = 3.641[1.213-10.927]).

CONCLUSIONS

Based on this preliminary study, we would suggest that pregnant women do not watch television before nocturnal sleep. While in the third trimester of pregnancy, total exposure time of television should be limited. Investigations from other areas and experimental studies should be conducted to verify the conclusion.

Effects of portable pedal machines at work on lipoprotein subfraction profile in sedentary workers - the REMOVE study

BACKGROUND

Sedentary behaviour at work is a major cause of atherosclerosis, particularly in tertiary workers. However, no studies have ever assessed the effect of active workstation on lipoprotein subfraction profile. This study aimed to evaluate the effect of 12-week portable pedal machines (PPMs) on lipoprotein subfraction profile among healthy sedentary workers.

METHODS

Healthy administrative workers were randomized into an intervention group using PPMs for 12 weeks or a control group using normal-desk. Lipoprotein subfractions were assessed using Lipoprint® electrophoresis. Main outcomes were explored using mixed models with sensitivity analyses (four models).

RESULTS

We included 40 participants (43.7 ± 8.6 years old, 100% women, BMI 23.8 ± 3.4 kg/m2; sedentary time at work 7.7 ± 1.8 h/day). Groups did not differ at baseline in any outcomes. 32 participants finished the trial. Changes in lipoprotein subfractions were especially marked for LDL profile. There was an interaction time x group for all parameters related to LDL and their subfractions: total LDL-cholesterol (p = 0.012), LDL particle size (p = 0.027), large LDL subfractions 1 and 2 (p = 0.001), and small dense LDL subfractions 3 to 7 (p = 0.046), using the crude model. The interaction reflects difference in the direction of changes between groups. The LDL particle size significantly increased in the intervention group (from 271.9 ± 2.5 at t0 to 272.8 ± 1.9 Ångström at t1, p = 0.037) while it did not change in the control group (272.5 ± 1.7 at t0 to 271.8 ± 1.5Å at t1, p = 0.52). All interactions were constantly significant whatever the models. Influencing variables were mainly stress at work that was associated with an increase in total LDL-cholesterol (coefficient 3.15, 95CI 0.20 to 6.11 mg/dl, p = 0.038), and BMI that was associated with Large-LDL, Large-HDL, IDL-C and triglycerides.

CONCLUSIONS

Lipoprotein profile was improved after a 12-week PPMs intervention at work in healthy administrative workers. Changes were mainly showed for LDL and LDL subfractions. Lipoprotein profile was worsened by stress at work, BMI and age.

TRIAL REGISTRATION

NCT04153214.

Replacement of Sedentary Time with Physical Activity: Effect on Lipoproteins

PURPOSE

Limited data on the relationship between physical activity and lipoprotein particle profiles exist. Our objective was to investigate associations between objectively measured physical activity and lipoprotein particle size and number, and specifically whether substituting daily sedentary behavior with light activity or moderate-to-vigorous physical activity (MVPA) is associated with beneficial alterations to the lipoprotein profile among adults and those at increased cardiometabolic risk (obese and insulin-resistant subjects).

METHODS

Sedentary behavior and physical activity intensity and duration were measured for 7 consecutive days using the GENEActiv accelerometer in a cross-sectional adult cohort (n = 396; mean age, 59.6 ± 5.5 yr). Lipoprotein particle size and subclass concentrations were determined using nuclear magnetic resonance spectroscopy. Isotemporal substitution regression modeling quantified the associations between replacing 30 min·d of sedentary behavior with equal amounts of light activity and MVPA on lipoprotein profiles.

RESULTS

Daily duration of MVPA was inversely associated with large VLDL particles and lipoprotein insulin resistance scores (P < 0.05, after adjustment for sedentary time and other confounding factors). Reallocating 30 min of sedentary time with MVPA, but not light activity, was associated with less large VLDL particles resulting in more favorable average VLDL particle size and improved lipoprotein insulin resistance score (P < 0.05). Analysis of high-cardiometabolic-risk groups revealed similar beneficial alterations to VLDL profiles (P < 0.05) with substitution of sedentary time for MVPA among the insulin-resistant (homeostasis model assessment for insulin resistance ≥75th percentile) but not the obese (body mass index ≥30 kg·m) individuals.

CONCLUSIONS

Daily MVPA duration and theoretical replacement of sedentary time with MVPA, but not light activity, were associated with less atherogenic VLDL profiles, particularly among the insulin-resistant individuals. These findings, which require further investigation, highlight the need to develop physical activity interventions aimed at improving atherogenic dyslipidemia and lowering cardiometabolic risk.

In cross-sectional observations, dietary quality is not associated with CVD risk in women; in men the positive association is accounted for by BMI

The role that BMI plays in the association between dietary quality and CVD risk is not known. We aimed to better understand this relationship using statistical methods which correct for sex-specific underreporting of dietary intake. Overall, dietary quality was assessed using the Healthy Eating Index (HEI) on data from 9797 non-pregnant adults (aged >20 years) who participated in the National Health and Nutrition Examination Survey from 2005 to 2010. CVD risk factors included blood pressure, fasting glucose and insulin, homeostatic models of insulin resistance (HOMA-IR), HDL- and LDL-cholesterol (HDL-C and LDL-C), TAG and C-reactive protein (CRP). We controlled for demographic and lifestyle covariates, and we used the population ratio approach (which adjusts for the underreporting of intake) to compare mean HEI scores between the top and bottom quartiles of covariate-adjusted CVD risk factors. In women, the total HEI score was not associated with any CVD risk factors (all Q>0·11). In men, the total HEI score was associated with covariate-adjusted residuals for fasting insulin (Q<0.001), HOMA-IR (Q<0.001), HDL-C (Q=0.01) and CRP (Q<0.001). When we additionally adjusted for BMI, the association with total HEI score was not significant (all P>0.10). In the present analyses, dietary quality was associated with five CVD risk factors in a sex-specific manner. Moreover, the association of BMI with CVD risk attenuated the relationship between CVD risk and diet, which suggests that BMI is an important factor in heart disease prevention.