Body Shape Trajectories Research Articles

Trajectory of body shape in early and middle life and all cause and cause specific mortality: results from two prospective US cohort studies

Objective To assess body shape trajectories in early and middle life in relation to risk of mortality.Design Prospective cohort study.Setting Nurses’ Health Study and Health Professionals Follow-up Study.Population 80 266...

Trajectory of body shape across the lifespan and cancer risk.

The influence of adiposity over life course on cancer risk remains poorly understood. We assessed trajectories of body shape from age 5 up to 60 using a group-based modeling approach among 73,581 women from the Nurses' Health Study and 32,632 men from the Health Professionals Follow-up Study. After a median of approximately 10 years of follow-up, we compared incidence of total and obesity-related cancers (cancers of the esophagus [adenocarcinoma only], colorectum, pancreas, breast [after menopause], endometrium, ovaries, prostate [advanced only], kidney, liver and gallbladder) between these trajectories. We identified five distinct trajectories of body shape: lean-stable, lean-moderate increase, lean-marked increase, medium-stable, and heavy-stable/increase. Compared with women in the lean-stable trajectory, those in the lean-marked increase and heavy-stable/increase trajectories had a higher cancer risk in the colorectum, esophagus, pancreas, kidney, and endometrium (relative risk [RR] ranged from 1.22 to 2.56). Early life adiposity was inversely while late life adiposity was positively associated with postmenopausal breast cancer risk. In men, increased body fatness at any life period was associated with a higher risk of esophageal adenocarcinoma and colorectal cancer (RR ranged from 1.23 to 3.01), and the heavy-stable/increase trajectory was associated with a higher risk of pancreatic cancer, but lower risk of advanced prostate cancer. The trajectory-cancer associations were generally stronger for non-smokers and women who did not use menopausal hormone therapy. In conclusion, trajectories of body shape throughout life were related to cancer risk with varied patterns by sex and organ, indicating a role for lifetime adiposity in carcinogenesis.

The association of body shape trajectories over the life course with type 2 diabetes risk in adulthood: a group-based modeling approach

PurposeLow birth weight is a well-recognized risk factor for type 2 diabetes (T2D), but less is known about risks associated with the evolution of body shape throughout life with incident T2D in adulthood. MethodsIn 80,110 women from the Etude Epidémiologique auprès de femmes de la Mutuelle Générale de l'Education Nationale (E3N) cohort study, trajectories of self-reported body shapes from age 8 years to 35–40 years were derived using a group-based modeling approach and studied in relation with incident T2D. ResultsCompared with women who maintained a stable midrange body shape trajectory from 8 to 40 years, women in all other observed trajectories were at a higher risk of developing T2D in adulthood: The highest risk was observed for women who were lean at age 8 years and had a sharp increase in body shape (hazards ratio = 2.91 [2.35–3.62]); their T2D risk was higher (P for homogeneity = .059) than for women who maintained the largest body shape (hazards ratio = 2.18 [1.76–2.69]). ConclusionsA group-based modeling approach has identified trajectories of body shape evolution with different risks of developing T2D in adulthood. A sharp increase in body shape after puberty in previously lean girls is a risk factor for the subsequent development of diabetes.

Body shape throughout life and the risk for breast cancer at adulthood in the French E3N cohort

Although earlier studies have indicated an inverse association between corpulence during childhood and the risk for breast cancer in adulthood, no study had evaluated body shape at different ages or body shape evolution in relation to the risk for breast cancer defined by menopausal status and hormone receptor status. Hazard ratios (HR) were estimated using multivariate Cox models in 81,089 women from the French E3N cohort to evaluate the risk for breast cancer associated with body shape (Sørensen's scale) at ages 8, menarche, 20-25, and 35-40 years. Six lifetime body shape trajectories were also estimated according to Nagin's approach to group-based trajectory modeling, and were analyzed in relation to the risk for breast cancer. During follow-up, 3573 breast cancer cases were diagnosed. At age 8 and at menarche, an increasing size of the body was associated with a significantly negative risk for estrogen receptor (ER)+/progesterone receptor (PR)+ postmenopausal breast cancer [both had a P(trend)=0.001; HR=0.80 (0.67-0.94) and HR=0.74 (0.64-0.86), respectively], for the largest body shapes compared with the first body shape. No significant association with body shape was found at the other ages. In terms of body shape evolution throughout life, women with a large body shape at menarche, irrespective of their body shape before or after menarche, tended to have a decreased risk for ER+/PR+ postmenopausal breast cancer compared with women who were constantly lean. Adjustment for current BMI or age at menarche did not modify any associations. Our study found an inverse association between adiposity at menarche and the risk for ER+/PR+ postmenopausal breast cancer, independent of corpulence at other ages. This work should encourage longitudinal studies with hormonal information to examine the underlying biological mechanisms.

Non-homogeneous combination of two porous genomes induces complex body shape trajectories in cyprinid hybrids

IntroductionHybridization is a common phenomenon in fish and is considered to be a major source of diversification. Deciphering the remoulding of genomic regions and phenotypes in zones where hybrid specimens occur is of particular interest to elucidate the emergence of evolutionary novelties. This approach is particularly challenging because the first step of hybridization seems to be the most important stage in the emergence of hybrid lineages. However, the signal can be significantly altered after only a few generations.ResultsWe studied 41 microsatellites and partial cytochrome b gene sequences in 970 specimens belonging to two fish species (Chondrostoma nasus and Parachondrostoma toxostoma) in allopatric/parapatric zones, hybrids between them in a natural sympatric zone: the Ardèche basin. We showed that the genomic architecture in hybrids presented pattern heterogeneity of selection for the different loci. Indeed, the upstream part of the river (Rosières and Labeaume) presented an overdominant fitness of heterozygotes (12.20%) corresponding to a genomic compatibility, and underselection was observed for 4.88%-7.32% of the loci tested indicating a genomic incompatibility. Moreover the upstream station (Rosières) presented a positive selection of invasive C. nasus homozygotes (17.07% to 21.95%) indicating that hybridization may increase the fitness of admixed individuals.We showed that hybrid morphology (body shape based on 21 landmarks) correlated with genomic dilution indicating a species fingerprint. However, we demonstrated that the hybrid morphology was not a linear modification between the two parental species but a trade-off between several correlated traits.ConclusionsHybrid specimens present a mosaic of genomic combination, showing regions with genomic compatibility and others with genomic incompatibility between the two species. Positive selection (invasive advantage ranging from 9.76% to 21.95% of the loci) was evidenced in the upstream part of the Ardèche indicating that environmental selection makes a substantial contribution. Although the presence of a dam is known to impose heterogeneous hybrid zones between these two species, we demonstrated in this study that a natural environment can also generate a hybrid zone with a large number (and diversity) of hybrids. The combination of the two genomes in the hybrids results in complex ontogenetic trajectories (with different morphological traits evolving at different rates) that correspond to novel developmental pathways.

Morphological and life-history shifts of the exotic cladoceran Daphnia exilis in response to predation risk and food availability

The zooplankter Daphnia exilis was found recently in reservoirs of central Chile. This species has been described as being tolerant to osmotic stress and chemical pollution, although the available information about its ecological properties is limited. Motivated by likelihood of being witnesses to a biological invasion, in this study we contribute to expand the knowledge of this exotic species through evaluating its ability to respond phenotypically to two major ecological factors: predation risk and food availability. Specifically, we analysed shifts in life-history and morphological traits of D. exilis in response to fish-released infochemicals, at different food densities. Our results revealed that the organisms were affected in their temporal trajectories of body size and shape, as well as in maturation time and fertility, in response to both predator cues and food availability. The presence of fish kairomones led to a decrease of age at maturity, and an increase of reproduction size and fecundity, especially at lower levels of resources. Our analyses indicated that asymptotic body size was affected only by food level, but the rate of increase in body size was sensitive to both fish kairomones and food level. The relative length of the tail spine decreased during early ontogenetic states, reaching a minimum around the age at maturity. This pattern was significantly enhanced in the presence of fish kairomones. However, our results did not match completely the typical responses of daphnids to fish kairomones.