'age stages' is a correct and usable phrase in written English.
It can be used to refer to the different stages or age ranges of a person's life, such as a young child, teenage years, twenties, thirties, and so on. For example, you could say, "Psychologists have studied the development of personality in children throughout the various age stages of their lives."
In this study, we used the pig as a model to perform a genome-wide survey of differences in DNA methylation and gene expression in a representative skeletal muscle (longissimus dorsi muscle, LDM) between two age stages in female pigs: young (0.5 years old) and middle-aged (MA, 7 years old) [ 10, 11].
Dorothy Wegman Raphaelson, who 80 years ago in chiffon, silk, feathers and lace floated across Jazz Age stages as a Ziegfeld Girl and went on to outlive all but one of her fellow dancers, died on Monday at her home in Manhattan.
Groups of different age stages have different development tasks and activities.
This may be due to the fact that perceived behavioural control is related to experience; and students or early age stages do not have the experience to judge how good they can perform (McGee et al. 2009).
Further, it is always assumed that there are two important age stages for the susceptible, a group of immature susceptible (S^{(1)}_{k}) who are less than 18 years old, and a group of mature susceptible (S^{(2)}_{k}) who are more than 18 years old.
As only the size of their fruit bodies differ from each other in appearance, researcher German Josef Krieglsteiner assumed that both are the same species in different age stages.
Moreover, at 28 days of age stage 5 neurons further decrease, their number becoming only 1/16 of stage 6 neurons.
In multivariate analyses age, stage and tumour type maintained significance.
As age, stage, performance status and comorbidity increased, prognosis worsened.
(Adjusted for age, stage, nuclear grade and Ki-67).
There was no difference in distribution of gender, age, stage among treatment modalities.
