Associations of parental age at pregnancy with adolescent cognitive development and emotional and behavioural problems: a birth cohort in rural Western China

BACKGROUND

The relationship between parental age at pregnancy and offspring development in low- and middle-income countries remains unclear. We aimed to examine the associations of parental age at pregnancy with adolescent development in rural China.

METHODS

We conducted a prospective birth cohort study of offspring born to pregnant women who participated in an antenatal micronutrient supplementation trial in rural Western China. Adolescent cognitive development and emotional and behavioural problems were assessed by using the Wechsler Intelligence Scale for Children-IV and the Youth Self-Report-2001, respectively. After accounting for the possible nonlinear relationships, we examined the linear associations between parental age (in years) at pregnancy and scores of adolescent cognitive development and emotional and behavioural problems by performing generalized estimating equations.

RESULTS

Among 1897 adolescents followed from birth to early adolescence, 59.5% were male with a mean age of 11.8 (standard deviation (SD): 0.8) years. The mean ages of mothers and fathers at pregnancy were 24.6 (SD: 4.4) and 27.9 (SD: 4.1) years old, respectively. All the P values of the nonlinear terms between parental age and adolescent development in all domains were greater than 0.05. Each one-year increase in maternal age at pregnancy was associated with a 0.29-point (95% confidence interval (CI) 0.06, 0.52) increase in the full-scale intelligence quotient in early adolescence. After parental age was categorized into quartiles, the total behavioural problem scores of adolescents with fathers with an age in the fourth quartile (Q4) were 6.71 (95% CI 0.86, 12.57) points higher than those of adolescents with fathers with an age in the first quartile (Q1), with a linear trend P value of 0.01. Similarly, higher scores (worse behavioural problems) were observed for internalizing behavioural problems and other emotional and behavioural symptoms related to anxiety, withdrawal, social problems, thought problems and aggressive behaviour.

CONCLUSIONS

At conception, older maternal age was independently linked to better adolescent cognitive development, whereas advanced paternal age was independently associated with a greater risk of adolescent emotional and behavioral problems. These findings suggest that public health policies targeting an optimal parental age at pregnancy should be developed in the context of offspring developmental consequences.

Porcine circovirus type 2 infection promotes the SUMOylation of nucleophosmin-1 to facilitate the viral circular single-stranded DNA replication

The mechanism of genome DNA replication in circular single-stranded DNA viruses is currently a mystery, except for the fact that it undergoes rolling-circle replication. Herein, we identified SUMOylated porcine nucleophosmin-1 (pNPM1), which is previously reported to be an interacting protein of the viral capsid protein, as a key regulator that promotes the genome DNA replication of porcine single-stranded DNA circovirus. Upon porcine circovirus type 2 (PCV2) infection, SUMO2/3 were recruited and conjugated with the K263 site of pNPM1's C-terminal domain to SUMOylate pNPM1, subsequently, the SUMOylated pNPM1 were translocated in nucleoli to promote the replication of PCV2 genome DNA. The mutation of the K263 site reduced the SUMOylation levels of pNPM1 and the nucleolar localization of pNPM1, resulting in a decrease in the level of PCV2 DNA replication. Meanwhile, the mutation of the K263 site prevented the interaction of pNPM1 with PCV2 DNA, but not the interaction of pNPM1 with PCV2 Cap. Mechanistically, PCV2 infection increased the expression levels of Ubc9, the only E2 enzyme involved in SUMOylation, through the Cap-mediated activation of ERK signaling. The upregulation of Ubc9 promoted the interaction between pNPM1 and TRIM24, a potential E3 ligase for SUMOylation, thereby facilitating the SUMOylation of pNPM1. The inhibition of ERK activation could significantly reduce the SUMOylation levels and the nucleolar localization of pNPM1, as well as the PCV2 DNA replication levels. These results provide new insights into the mechanism of circular single-stranded DNA virus replication and highlight NPM1 as a potential target for inhibiting PCV2 replication.

How the marketing practices of commercial milk formula companies impact infant breastfeeding practices in China

BACKGROUND

The marketing practices used by commercial milk formula (CMF) companies undermine breast feeding. However, it remains unclear how specific types of marketing practices result in suboptimal breast feeding.

OBJECTIVES

We aimed to examine the associations of CMF marketing practices with breastfeeding outcomes, determine the influencing pathways, how it changes the perceptions and attitudes of mothers towards CMF, and how it impacts breastfeeding outcomes.

METHODS

A cross-sectional survey was conducted in Beijing and Jinan, China that mapped the CMF marketing practices in 2020. Mothers were interviewed about the feeding practices for the youngest child under the age of 18 months. Maternal attitude towards CMF was assessed using a set of five questions. Six common CMF marketing practices were reviewed. A logistic regression was performed to examine the associations between the CMF marketing practices and predominant breast feeding, with adjustments for maternal age, education, occupation, socioeconomic class and caesarean section. Furthermore, a path analysis was conducted to explore the pathways between the CMF marketing practices, maternal attitude towards CMF and predominant breast feeding.

RESULTS

A total of 750 mothers were interviewed, with 20.0% of mothers predominantly breast feeding their young children. Two marketing practices, online engagement with CMF companies and promotions and discounts, were statistically associated with a lower likelihood of predominant breast feeding, with an adjusted ORs of 0.53 (95% CI 0.35 to 0.82) and 0.45 (95% CI 0.22 to 0.92). Furthermore, per CMF marketing practice increase mothers concurrently exposed to was associated with a 0.79 (95% CI 0.68 to 0.92) times lower likelihood of predominant breast feeding. In addition, online engagement and free formula samples distributed in hospitals had indirect effects on suboptimal breastfeeding outcomes, which was partly mediated by positive maternal attitude towards CMF.

CONCLUSIONS

CMF marketing practices were associated with a lower likelihood of optimal breastfeeding through influencing the maternal attitude towards CMF.