Study design and setting

We carried out interrupted time-series analyses (ITSA²⁰) to quantify the adjustments in EBF prevalence, following the implementation of two insurance policies and the COVID-19 pandemic. We measured EBF with aggregated municipal (municipality is the smallest administrative unit in Chile) knowledge. Administrative permissions had been required to make use of and entry the first healthcare system nationwide database employed on this examine.

In temporary, an ITSA assesses whether or not there are modifications over time within the traits of a particular consequence (on this case, EBF), after the introduction of an intervention and compares them to an estimated counterfactual pattern based mostly on pre-treatment observations (historic management group)²¹.

This is a nationwide examine, with knowledge from the entire public healthcare system service customers, which compromises roughly 80% of the overall Chilean inhabitants²². The different 20% are attended within the non-public well being system, which is fully based mostly on non-public insurers²³.

Variables and knowledge assortment

Municipal unique breastfeeding share

EBF (consequence) included month-to-month data from 345 Chilean municipalities. Data had been obtained from public healthcare system feeding registries recorded throughout well being checkups by well being professionals at 3 and 6 months. Health professionals registered if a baby had EBF, partial BF, or method, or stable meals, following the WHO definition of EBF: “Exclusive breastfeeding refers to being uniquely fed by breastmilk, from the mother, wet nurse, or pumped milk, without receiving any other kind of food or liquid unless a health professional prescribes a medicament, such as syrup or drops, vitamins or minerals”²⁴. This definition consists of youngsters who often obtain a small amount of water. The knowledge of youngsters with up-to-date checkups had been collected in the identical method because the EBF knowledge. The following definition was used for up-to-date checkups: “children who attended health checkups performed at the age of one, three, six, 12, and 24 months²⁴”. Using the class “children fed with EBF”, the EBF share was calculated utilizing the month-to-month absolute numbers of youngsters with EBF at 3 and 6 months of every PHCC and absolutely the variety of youngsters with well being checkups from the identical age group and site.

Each PHCC is chargeable for sending month-to-month aggregated knowledge to the Regional Health Office, the place the data is consolidated by municipality (every municipality has a couple of PHCC), revised, and despatched to the Health Ministry’s Department of Statistics and Health Information.

We included the EBF cut-off of three months as a result of, in Chile, the earlier 12-week ML corresponded to 2 and a half months; therefore EBF at 3 months may present a comparability earlier than and after the extension of the ML. In addition, EBF at 6 months was assessed as a result of this corresponds to the WHO unique breastfeeding advice^4,25.

Interventions

This examine included three time-events:

• October 2011: implementation of 12 further weeks of totally paid obligatory ML, bringing the overall to 24 weeks. The introduction of the prolonged ML additionally integrated extra versatile phrases to entry ML, aiming to extend ML entry in ladies with casual jobs. The preintervention interval was from January 2009 to September 2011, and the intervention interval was from October 2011 to December 2014.

• January 2015: The P4P technique was applied to encourage well being professionals to extend the promotion and assist of EBF to attain the 6-month EBF nationwide objective. The preintervention interval was from January 2009 to December, and the intervention interval was from January 2015 to November 2020.

• March 2020: The starting of the COVID-19 pandemic in Chile. COVID-19 represented a discount in healthcare providers, together with EBF promotion. EBF knowledge had been obtainable till November 2020. The preintervention interval was from January 2015 to March 2020, and the intervention interval was from April 2020 to November 2020.

Covariables

Urban–rural areas

Rural municipalities had been outlined in response to the parameters utilized by the 2017 Chilean Census: “a rural entity is a human settlement with a population of 1000 or less, or 1001 and 2000, where more than 50% have jobs in the primary sector (farming, fishing, agriculture, and similar), or where there is a small settlement that meets the population criteria to be defined as urban, but not the requirements of amassing, continuity or concentration of constructions”. In addition, we additionally thought-about rural a municipality that had greater than 50% of its inhabitants residing in rural areas. Thirty p.c of the municipalities (106 municipalities) had been labeled as rural (roughly 3.5 million folks)²⁶.

Geographic macrozones

Municipalities had been aggregated into 5 (topographic) macrozones, that are outlined by morphology, geography, pure sources, local weather, and the kind of work their inhabitants carry out: Big North, Small North, Central, Southern, and Austral (Fig. 1)²⁷. These 5 macrozones are generally known as the financial and geographical macrozones. For instance, the inhabitants within the Northern macrozone works primarily in mining and reside in remoted desertic areas, whereas, within the Austral zone, the primary financial growth is said to agriculture and exports²⁸.

Map of Chilean topographical zones.

Other covariables included within the analyses

Seasonality

Seasonality was included within the fashions as a fixed-effect month-to-month dummy^{1,2,3,4,5,6,7,8,9,10,11,12}, with the primary measure (January) serving because the reference class. Seasonal dummies assist to seize attainable seasonal results.

ML entry

The ML month-to-month entry was calculated as a nationwide share utilizing absolutely the variety of ML issued within the Public Health System (Maternity Leave Management and Information System [SIMAT] from the Social Welfare Superintendence, SUSESO)²⁹ and the variety of newborns within the public well being system. The common ML entry fee throughout the entire examine interval was 20% (starting from 14 to 24%), with no main improve or lower after the implementation of the additional 12 weeks of ML. These outcomes on ML entry agreed with a earlier examine that reported related traits and low entry of ML in ladies accessing the general public healthcare system³⁰. Although the ML is obligatory by legislation for all moms, solely moms with a proper contract or freelancer contracts with pension scheme up-to-date funds can entry the 24-week ML.

Data evaluation

The following regression mannequin was specified to estimate the change in municipal EBF prevalence after every of the three-time occasions:

EBF represents the end result at time level (months) T for every equally spaced time level t at every particular person degree _i.. T_ti signifies the time because the starting of the examine (as much as 143 months). X_ti represents an intervention dummy variable (preintervention interval 0, intervention 1), and X_tiT_ti is an interplay time period. β₀ is the intercept and EBF prevalence originally of the examine interval. β₁ represents the end result pattern earlier than the intervention, which helps to quantify the pattern within the absence of the intervention. β₂ is the slope change within the consequence following the intervention. β₃ estimates the change within the EBF pattern in the long run after the intervention, evaluating it with the EBF pattern earlier than the intervention. ({beta }_{4})(months 1–12) represents the seasonality adjustment as a seasonal dummy. E_ti represents the errors within the mannequin over time. In this examine, the time collection dataset had three breakpoints (prolonged ML, P4P technique, and COVID-19 pandemic), every analysed utilizing the above mannequin in impartial segments to keep away from an overlapping impact³¹. All the above-mentioned coefficients are proven within the outcomes tables, however the outcomes and dialogue will refer solely to the slope change coefficient (β₂).

The ITSA was performed utilizing the “XTITSA module” in Stata Software (v.17), contemplating every municipality as individual-level knowledge^20,32. Autocorrelation was evaluated utilizing the Durbin-Watson take a look at. As small proof of autocorrelation was recognized, analyses had been carried out with correction for autocorrelation. The Cochran Q take a look at for heterogeneity was used to analyse attainable statistical variations between strata of city and rural areas and within the 5 geographic macrozones, utilizing the nationwide outcomes as reference for the city and rural analyses and the Central Zone as reference for the macrozone analyses³³.

Ethics

This examine was authorized by the Ethics in Human Research Committee (Comité de Ética de Investigación en Seres Humanos) of the Faculty of Medicine of the University of Chile, below the Project: No 069-2021 and file quantity N° 045. Informed consent was not required as a result of the databases used on this examine had been anonymised and the data had been aggregated. Our examine didn’t contain human or animal laboratory experiments.