Jihong Liu

Dog Ownership during Pregnancy, Maternal Activity, and Obesity: A Cross-Sectional Study

The Avon Longitudinal Study of Parents and Children (ALSPAC) is an observational study of 14273 UK pregnant singleton mothers in 1990/1991. We examined outcomes of self report of strenuous activity (hours per week) at 18 and 32 weeks of gestation, hours spent in leisure-time physical activities and types, and pre-pregnancy body mass index (BMI); overweight status was defined as pre-pregnancy BMI≥25 and obesity BMI≥30. Pet ownership and activity data were reported for 11,466 mothers. Twenty-five percent of mothers owned at least one dog. There was a positive relationship between participation in activity at least once a week and dog ownership (at 18 weeks, Odds ratio 1.27, 95% confidence interval 1.11–1.44, P<0.001). Dog owners were 50% more likely to achieve the recommended 3 hours activity per week, equivalent to 30 minutes per day, most days of the week (1.53, 1.35–1.72, P<0.001). Dog owners were also more likely to participate in brisk walking activity than those who did not have a dog (compared to no brisk walking 2–6 hrs per week 1.43, 1.23 to 1.67, P<0.001; 7+ hrs per week 1.80, 1.43 to 2.27, P<0.001). However, no association was found with any other types of activities and there was no association between dog ownership and weight status. During the time period studied, pregnant women who had dogs were more active, through walking, than those who did not own dogs. As walking is a low-risk exercise, participation of pregnant women in dog walking activities may be a useful context to investigate as part of a broader strategy to improve activity levels in pregnant women.

Physical activity during pregnancy and language development in the offspring

BACKGROUND In rodents, physical activity during pregnancy has been associated with improved learning and memory in the offspring. We used data from the Avon Longitudinal Study of Parents and Children (born in 1991-92) to investigate maternal physical activity during pregnancy and offspring language development. METHODS At 18 weeks of gestation, women reported the hours per week they participated in 11 leisure-time physical activities and the hours per week spent in general physical activity (leisure, household and occupational). Caregivers completed a modified MacArthur Infant Communication scale at 15 months. Verbal intelligence quotient (IQ) was measured at age 8 years. Regression analysis was used to examine the associations of physical activity with MacArthur score (more than 75th percentile) and verbal IQ. The number of participants available for analyses ranged from 4529 to 7162. RESULTS Children of women in the two highest quintiles of leisure activity (compared with no leisure activity) were more likely to have high 15-month MacArthur scores (adjusted odds ratio 1.2 [95% confidence interval 0.9, 1.4] and adjusted odds ratio 1.4 [95% CI 1.1, 1.7], respectively). Leisure activity was not associated with IQ, while general physical activity was linked with lower verbal IQ (1 and 3 points lower for the two highest quintiles). CONCLUSIONS The most robust finding was a transient increase in offspring vocabulary score at young ages with maternal leisure activity. Differences in the associations with leisure-time physical activity compared with general physical activity need further exploration.

Effects of cardiorespiratory fitness on aging: glucose trajectory in a cohort of healthy men

PURPOSE We modeled the age-related trajectory of glucose and determined whether cardiorespiratory fitness altered the trajectory in a cohort of men from the Aerobics Center Longitudinal Study. METHODS A total of 10,092 men free of diagnosed diabetes, cardiovascular disease, and cancer, ages 20 to 90 years, completed from 2 to 21 health examinations between 1977 and 2005. Cardiorespiratory fitness was measured by a maximal treadmill exercise test and normalized for age. The covariates included waist circumference, hypertension, elevated cholesterol, smoking behavior, and physical activity. RESULTS Linear mixed models regression analysis showed that fasting glucose increased at a linear rate with aging. Glucose increased at a yearly rate of 0.17 mg/dL (95% confidence interval: 0.16-0.19). Fitness had little influence on the aging glucose trajectory below age 35, but significantly influenced the trend after age 35 (P for interaction < .001). The aging-related glucose increases in low-fitness men (0.25 mg/dL per year) was greater than average-fitness (0.15 mg/dL per year) and high-fitness (0.13 mg/dL per year) men. CONCLUSIONS The aging-related fasting glucose increases in low-fitness men was nearly double that of high-fitness men. Our results may suggest that it is possible to delay the age-related glucose impairment through increasing ones fitness level.

Association of Obesity with Onset of Puberty and Sex Hormones in Chinese Girls: A 4-Year Longitudinal Study

Objective To examine the influence of childhood obesity on the early onset of puberty and sex hormones in girls. Methods Healthy girls with different percentages of body fat at baseline (40 obese, 40 normal, and 40 lean) were recruited from three elementary schools in Shenyang, China. These girls (mean age 8.5 years) were also matched by height, school grade, Tanner stage, and family economic status at baseline. Anthropometry, puberty characteristics, and sex hormone concentrations were measured at baseline and at each follow-up visit. The generalized estimating equation model and analysis of variance for repeated measures using a generalized linear model were used to determine the differences in puberty characteristics and sex hormones among three groups. Results Over 4 years, mean age of breast II onset was earlier among obese girls (8.8 years) than normal girls (9.2 years) and lean girls (9.3 years). The prevalence (%) of early-maturation in the obese, normal, and lean groups was 25.9%, 11.1%, and 7.4%, respectively. Obesity was associated with an increased risk for breast stage II (year 2: RR, 6.3; 95% CI, 1.9–21.1 and year 3: RR, 6.9; 95% CI, 0.8–60.1). None of the girls experienced menarche in the first year; however, by the fourth year 50.0% of obese girls had menarche onset, which was higher than normal weight (27.5%) and lean girls (8.1%). The mean estradiol level increased with age in the obese, normal, and lean groups. The mean estradiol concentration was higher in obese girls than in normal and lean girls throughout the 4-year period (P<0.05). Conclusions Childhood obesity contributes to early onset of puberty and elevated levels of estradiol in girls.

Periodontal treatment among mothers with mild to moderate periodontal disease and preterm birth: reanalysis of OPT trial data accounting for selective survival

Background The Obstetrics and Periodontal Therapy (OPT) study, a randomized controlled trial, reported no effect of periodontal treatment on preterm birth. Even though there were more spontaneous abortions or stillbirths in the control group, sensitivity analyses using conventional approaches did not change the results. The development of newer epidemiological methods to assess bias caused by the truncated outcome, and the availability of OPT study data in the public domain, allowed us to reanalyse these data. Methods We used the survivor average causal effect (SACE), also known as the principal strata effect, to correct potential bias resulting from unequal survival of fetuses in the treatment and control arms of the OPT study. Results The risks of preterm and spontaneous abortions or stillbirths were respectively 49/413 (11.86%) and 5/413 (1.21%) in the periodontal treatment group, and 52/410 (12.68%) and 14/410 (3.33%) respectively in the control group. The risk differences (%) comparing periodontal treatment and control groups were -0.82%: 95% confidence interval (CI) -5.30% to 3.67% for preterm birth, and -2.12%: 95% CI -4.14% to -0.11% for spontaneous abortions or stillbirths before correction. Risk differences for preterm birth comparing periodontal treatment and control groups increased in magnitude, reached statistical significance and showed a beneficial effect of periodontal treatment after correction for bias using SACE. Conclusions Periodontal treatment provided to mothers with mild to moderate periodontal disease before 21 weeks of gestation may prevent preterm births.

Maternal Obesity, Gestational Weight Gain, and Asthma in Offspring

Introduction Obesity is common among women of childbearing age; intrauterine exposure to maternal obesity or gestational weight gain may influence the development of asthma in early childhood. We examined the relationships of maternal obesity and gestational weight gain with asthma in offspring. Methods We used data from the Early Childhood Longitudinal Study–Birth Cohort, which has a nationally representative sample of children followed from birth in 2001 through age 4 (n = 6,450). Asthma was based on parental report of a medical professional’s diagnosis. We used generalized estimating equation binomial models to compute adjusted odds ratios (ORs) of childhood asthma with maternal obesity and 4 measures of gestational weight gain. Results Compared with children of normal-weight mothers, children of obese mothers had increased risk of asthma (adjusted OR, 1.63; 95% confidence interval [CI], 1.26–2.12) by age 4, and children born to overweight mothers had similar risk (adjusted OR, 1.25; 95% CI, 0.99–1.59). Extreme-low weight gain (<5 kg) and extreme-high weight gain (≥25 kg) were associated with increased risk of asthma; however, the following measures were not significant predictors of asthma: meeting gestational weight gain recommendations of the Institute of Medicine, total gestational weight gain, and weekly rate of weight gain in the second and third trimesters. Conclusion Extreme-low or extreme-high gestational weight gain and maternal obesity are risk factors for early childhood asthma, further evidence of the long-term impact of intrauterine exposure on children and the need to target preconception care to improve child health indicators.

Pregnancy Interventions or Behaviors and Cardiometabolic Biomarkers: a Systematic Review

While normal pregnancy is characterized by changes in serum glucose and lipid levels, overweight and obese women exhibit marked alterations in the trajectory of these changes. Reviews have been published assessing the efficacy of behavioral interventions for weight management during pregnancy. No reviews, however, have examined the metabolic impact of such lifestyle changes/behaviors. We conducted this systematic review summarizing evidence to July 2015 from both trials and observational studies examining the impact of lifestyle interventions or healthy behaviors (diet and/or exercise) among pregnant women on cardiometabolic biomarkers measured during pregnancy. We found that studies are conflicting and have small sample sizes. A better understanding of the underlying mechanisms that may mediate the effects of nutrition and physical activity on gestational weight gain, pregnancy complications, and long-term cardiometabolic outcomes is needed with particular focus on high-risk groups of overweight and obese women.